Error Coins, an Introduction

By on 16th December 2017

UK error coins are a fascinating and still fairly non mainstream side-line to regular coin collecting. Ignore the headline grabbing stories about error coins that are worth ‘a fortune’ that the tabloid/clickbait press push out. Most error coins are usually fairly low value and many minor errors can be picked up for just a few pounds. UK error coins, just like normal coins, are only worth what someone is willing to pay for them. That worth is strongly influenced by a number of factors including demand, rarity and the attractiveness of the error. An extra factor that plays a big role with error coins is their severity or unusualness.

Error coins have never really been a big deal in the UK until recently where interest in them has grown. An increase in people collecting coins has lead to more people looking closer at coins and noticing errors. People are now able to instantly share images of unusual coins on social media, prompting others to look for unusual coins. More suspected error coins are being discovered, shown and discussed. Some error coins end up being exposed in the press (and many aren’t actually errors at all!), usually as a result of people asking silly inflated prices for coins on eBay, that are completely utopian and where ‘sales’ at such prices are unverifiable and are very often not genuine or completed.

Fake errors

The recent increase in interest and higher demand for UK error coins has also prompted many unscrupulous people to create home made error coins that have clearly been manipulated and were not originally made like that. This is essentially post-mint damage and is something which has been especially rife with the new 12-sided £1 coin. Unfortunately, due in part to the demand fuelled by the tabloid stories and people not really understanding what they are buying, many have paid too much money for ruined coins that technically no longer even have a valid face value. To be able to spot shed-made ‘errors’ it’s important to understand how coins are made, especially the bi-metallic £2 and £1 coins (some more on that further down).

Minor UK error coins (and non errors) include:

Here are some error types that I have observed on UK error coins over the years. There are other types of UK error coins and this list is not meant to be comprehensive. I’ll try to add pictures where possible. If you have an error coin that is not shown and can provide good quality images, please let me know.

The die chip at the bottom of this 2008 20p very much resembles an upside down ‘1’.

1. Die chips …

Very common on modern (post approx. 2000) UK coins. Die chips are raised blob-like lumps on the surface of the coin. They are usually on a raised part of the design as opposed to on the lowest flat areas. Die chips on earlier coins are rarer, which seems to indicate to me that the Royal Mint procedure for striking coins has changed over the years. Perhaps they are saving money by using dies beyond their normal accepted lifetime or by not properly ensuring that coins are of high enough quality before they end up in circulation. Larger die breaks that also involve the rim are known as cuds. Die chips can be more interesting if they resemble something that looks intentional; see also die cracks, below.

2. Die cracks …

The same principle as with a chip, i.e. the die that was used to strike the coin is damaged through excessive use. Instead of a blob, a cracked die results in a thin raised line on the surface of a coin. The line can turn into a larger blob if the faulty die isn’t changed and breaks further. The lines often pass through raised design elements like lettering and can sometimes run right to the edge of the coin. Cracked dies have resulted in a recent coin anomalies where the crack happen to look like an extra feature, e.g. on the so-called ‘cat on mast’ 2015 Royal Navy commemorative £2.

I originally thought the 2016 Peter Rabbit 50p with ‘extra whisker’ was a die crack. This extra whisker is caused by a damaged die, but most likely damage from being scratched by part of the machinery called a feeder finger.

3. Unstruck blanks/planchets/flans ….

An unstruck large type (pre 1997) 50p blank, probably from the late 1960s.

Blanks, or more accurately in most cases ‘planchets’, are pieces of shaped metal that haven’t been struck into coins. Higher denomination coins with edge lettering have the edge motto imparted onto them during a separate process and before they are struck. It is more common where blank £2 or old £1 coins are encountered, to find them with clear edge lettering but omitting the milling. The rim milling is imparted by the retaining collar at the same time as the design detail is struck between the two dies. Most blank planchets have a raised rim, as this is also imparted onto the disc before it gets struck between the dies in a process known as ‘up-setting’. Unstruck coins are unusual but can normally be obtained quite cheaply.

Blank coins with an edge motto that was only used for one particular coin design during one year only, and can therefore be properly attributed, are more desirable than a blank piece of metal that can only be attributed to a particular denomination.

Note that fake blank coins can potentially be man-made by smoothing down both sides of a normal coin. These are usually obvious to spot, as the surfaces often show tooling marks and/or are excessively polished. The thin layer of removed metal means that the fake ‘blank’ will weigh significantly less than a real one.

Note also, that 20p coin blanks are completely round. They are shaped entirely by the retaining collar during the striking process.

4. Clipped flans …

A 1969 10p struck on a (curved) clipped flan.

Round or shaped coin blanks are cut out of sheets of metal. This is done at high speed and sometimes something goes wrong and blank pieces of metal are produced that have been clipped on the edge (at least once) by the sharp press that cuts out the metal discs/shapes. When these irregular shaped blanks are struck into coins and released into circulation they are known as a ‘clipped planchet’ or ‘clipped flan’ error. The clip itself can range in size from being just a tiny, almost unnoticeable irregularity on the rim to being a fairly large crescent shaped chunk out of the coin. It is also possible (and much rarer) for a coin to have more than one clip, in different positions. When blank coins are cut too close to the edge of the strip of metal it results in a straight clip.

5A. Partial collar error …

When the planchet (blank piece of metal) is struck between the dies, it is at the same time surrounded by a retaining collar which ensures the resulting coin is perfectly shaped. Either round or with ‘sides’ in the case of the new £1, the 50p and the 20p. For coins with edge milling the collar also features a negative ridged structure to impart the ridges (millings) onto the edge. It all happens very quickly. If a planchet isn’t positioned properly within the collar it results in an odd edge. Sometimes a raised lip, either partially or all the way around the coin or a smooth section of the rim where it should feature milling.

Coins that are not round are more susceptible to suffering from partial collar problems. The new £1 is by far the most commonly encountered coin with partial collar errors.

A large type 50p that has suffered a slipped collar during striking.

5B, Broadstrikes (struck without collar) …

A broadstrike 2017 50p. This example is about 29mm in diameter (normal 50p coins struck within the retaining collar are 27.3mm in diameter).

When a planchet is struck between dies without its retaining collar it results in an error known as a broadstrike. Without the collar, metal is able to flow outside of the normal constraints. Broadstrike coins weigh the same as normal coins of the same type, but are a little larger and thinner.

6. Lamination errors …

Sometimes when the blanks are not properly prepared, fragments of flat metal can splinter off from them, either before the coins are struck, or afterwards. This can result in what appears as hollow areas on the coin’s surface or in thin bits of metal that appear slightly raised. This kind of error is not particularly common on UK coins, but usually it’s viewed as ‘one of those things’ and lamination error coins are mostly not that attractive. There are some more extreme cases which are more desirable.

7. Die clash or ghosting …

A 50p struck with dies that have clashed at some stage. Note the outline of the Queen.

Are caused by different issues, but can result in a similar effect on coins. By far the most commonly encountered of the two on modern UK coins is ‘die clash’, which seems to have affected a number of 2016 Jemima Puddle-Duck 50p coins and some 2017 Isaac Newton 50p’s but can potentially affect any coin. Coins with die clash have elements – often just outlines – of the design from one side appearing on the opposing side. With the aforementioned Puddle-Duck 50p, the obverse has a faint outline of the duck and the reverse has a faint outline of the Queen. It is the result of the two dies coming together at great force with no coin-to-be between them and partially imparting their images on to the opposing die.

Ghosting, on the other hand, is caused by metal flow and is due to an imbalance of raised detail (or incuse detail on the dies) on each side of the coin. It was common on the early coins, particularly the pennies, of King George V.

8. Slight tone differences …

Due to a number of possible causes during manufacture and sometimes environmental factors after a coin is circulated, coins can sometimes appear to be a different tone compared like for like. Some can have a streaky appearance, some appear much darker than normal. This can be curious and there are certain coins for which it seems to happen more often. It’s not really viewed as a serious fault.

9. Dark ring on £1 …

A 2017 £1 coin showing the burnt-on dark rim around the outside of the silver coloured part.

Affecting mainly the new £1 coin but also some £2 coins – sometimes one or both sides have a dark coloured ring around the inner silver coloured part. This stain cannot be removed and is thought to be grease/gunk that was on the dies or planchet and has been burnt onto the coin due to the heat generated during the striking process.

An old 1960s florin with very weak lettering to the left of the Queen, almost certainly due to the die being filled with grease/crud.

10. Grease/crud blocked dies …

When excessive grease or foreign matter gets into the dies it can result in missing detail on the finished coin. The most common result from grease in the die is very weak or partially missing lettering on the coin.

11. Stripped plating …

Some UK coins are made of a cheap steel core, plated with a more attractive metal that is less liable to corrosion. Since 1992 the 1p and 2p are made of steel, plated with a very thin layer of copper. Coins have been seen where this thin layer of copper is missing, most likely they were made that way and the blank piece of metal was missing its copper layer when struck. 1p and 2p coins that are silver coloured (and magnetic) are a fairly common occurrence as error coins go. To add confusion, it is actually possible to strip the copper layer from a 1p or 2p without adversely affecting the steel core, and with a resultant coin which looks very much like it was made that way.

12. Corrosion bubbles …

1993 2p with a corroding steel core.

As mentioned above, the 1p and 2p are steel, plated with copper. The 5p and 10p also have a steel core and are plated with nickel for a more attractive appearance. If the thin layer of external metal is compromised, dampness can enter. In extreme cases the coin can form large bubbles on the surface while quietly rusting from the inside. In the early stages this can also resemble a die chip (see no.1). It is likely that contaminants were present between the core and thin plated layer when the coin was made. It is also possible that the core has started to rust due to damage to the outer layer through use.

13. Edge lettering, words not properly formed …

Very commonly observed on the Guy Fawkes £2 coin. It can, in extreme cases can have edge lettering that reads ‘PEMEMBEP PEMEMBEP THE FIFTH OF NOVEMBEP’ (the R’s resembling P’s). The tabloids made a big thing of it when it first came to light. That resulted in people speculating and paying far too much for such coins on eBay etc, before it all blew over. It is no longer considered a big deal. In fact Guy Fawkes coins with P’s instead of R’s are very common.

The edge motto is rolled onto the edge of the blank coin and either the raised tails of the R’s were broken, or the edge lettering was too weak and/or the edge milling too strong resulting in parts of letters becoming virtually lost within the vertical milling. Similar problems are noted with other letters on other £2 coin types and they don’t usually attract a premium.

14. Queen wearing a necklace …

This is not an error at all, it’s a twenty+ year old urban myth that still refuses to completely dissipate! In 1998 the Queen’s portrait was changed at about the same time as the introduction of the new bi-metallic £2. Lots of new £2 coins were struck in 1997 featuring the third portrait of the Queen, which show her wearing a necklace. Lots were also struck dated 1998 showing the fourth portrait of the Queen. Both types were first released in mid 1998 and a rumour spread that the £2 coins with ‘the Queen wearing a necklace’ were in some way special. I can remember my friend’s brother selling them to a bloke in his local pub for £20! They are very common and should never have been worth more than face value.

15. Bi-metallic coins with lost detail in the metal join …

This isn’t really an error either, but is also something that comes up a lot. When a bi-metallic coin is struck, if something isn’t set up perfectly central, or the position of the outer ring and inner round part isn’t exactly as it should be, it can result in coins being produced with slight gaps between the two metal parts. This can result in design elements being missing. Usually the small beads around the rim of the silver part suffer most. In more severe cases, elements of the main design can also be lost. The Royal Mint do seem to be aware of the quality issues affecting bi-metallic coins as their higher-end coins are actually made differently and the metal joins tends to be much neater and the middle part almost always perfectly central.

Two examples of coins that often have common problems with the metal join are the 2006 Brunel portrait coin which often reads ‘TWO DOUNDS’ as the tail of the ‘P’ has been lost in the join of the two metals, or on the 2014 Kitchener WWI coin where the tail of the ‘Y’ from the ‘YOU’ above the date is also missing for the same reason. It’s unfortunate, but it is really down to the way the circulation coins are made at such speed and there will inevitably be imperfections.

16. The edge lettering is the wrong way up …

No it isn’t! The edge wording orientation is completely random. It never used to be a thing. No one cared or even noticed it until the Sun reported (in one of the worst pieces of coin related journalism that I have ever read) during December 2016 that the edge lettering should be the right way up when the coin is held with the Queen facing upwards. I have no idea where they got this information. It was completely made up and even the Royal Mint must have been sick of the enquires. They published a piece online putting it straight.

More serious errors include:

17. Rotated dies (the more rotated the better) …

A 2015 Britannia £2 coins with a mirror reflection of its reverse which clearly shows that Britannia is almost upside-down.

It shouldn’t be possible, as the dies should be fixed in place and unable to move. Occasionally one of the dies that are used to strike the blank planchets into coins rotates slightly. It results in a coin that doesn’t have the tops of each side in the same opposing position. Die rotation errors are very rare for pre 2008 coins, but are known to exist for many modern coins. The more severe the rotation, the more desirable is the resultant coin. The most desirable die rotation error coins are ones where there is a 180 degree difference between both sides. Values for die rotation errors can vary from as low as a few times face value to hundreds or even (on very rare occasions) thousands of pounds, depending on the severity, rarity and how much people are prepared to pay to own it.

Slight die rotations on 7 sided coins (the 20p and 50p) are fairly common for certain types.

18. Clearly doubled lettering or other elements …

Doubled details, where some digits/letters or other design elements appear twice is most commonly caused by something known as ‘mechanical doubling’, or ‘machine doubling’. Mechanical doubling is caused when a coin is struck where there has been a simultaneous slight movement of a die, resulting in a double impression of design elements. Such doubling, although rare on UK coins, is considered a minor striking error and isn’t such a big deal in terms of desirability.

Very weak, usually raised shadows or faint hints at duplicate detail around design elements (mostly letters and digits) that tend to extend towards the rim of the coin is caused by die fatigue. This happens when dies are used well beyond their normal working life – each coin they have struck has taken its toll on the surface of the die and the repeated metal flow into the incuse die slowly wears out its detail. Often coins struck with worn dies can have letters and digits that appear fatter and less sharp. Worn dies that are not replaced can go on to strike many more coins with these features. This phenomenon is common and such coins are not considered valuable.

Part of a 2010 technology £2 coin suffering from doubled letters.

A much scarcer and much more pronounced form of doubled detail is caused when a coin is struck from a die that has been engraved with doubled detail in the first place. Doubled die coins are caused by a problem in what is known as the hubbing process, which is an earlier stage of coin production where master dies are created from a relief (raised) impression of how the coin side should look. The hubbing process that imparts the incuse (negative) detail on the master dies doesn’t happen once per master die and it is these multiple passes that can, if there is a slight slippage or movement, result in a master die with doubled features.

A recent example of this phenomenon occurs on the 2010 technology £2 coin, where most of the letters on the obverse are very clearly doubled – this has been seen on many 2010 £2 coins so is assumed quite common.

19. Mismatched BU and circ dies (known for some gold coins) …

Something I have seen concerning some gold coins recently. The dies for proof coins and the dies for standard coins or for BU quality coins are quite different, even though they are of the same basic design. Proof dies are produced more carefully and usually have frosted raised details to contrast their mirror-like flat areas. Other types of coin finishes don’t have such a contrast between the flat and raised parts. Coins struck with mis-matching sides are caused by someone not paying attention. Resulting in coins with one side of an inferior finish to the other.

20. Fried egg £1/£2, Pill not centred …

A ‘fried egg’ error new £1 coin. Not all have a visible gap between the metals opposite the breach.

Basically a bi-metallic coins that looks a bit like a fried egg! Thought to be due to the pill shaped round part of the coin not lining up properly with the outer ring just before it’s struck. This causes it to be struck partially on top of the ring and not completely within it. The metal-on-metal means extra mass where it shouldn’t be and this is pushed out towards the edge sometimes leaving a gap between the two metals in the opposing join.

This error is known to be fairly common on the new bi-metallic £1 coin and on some 2015 £2 technology coins. It certainly isn’t exclusively a UK error though and occurs on many other foreign (e.g. Euro) bi-metallic coins.

Some of the most serious (and valuable) error types include:

21. Withdrawn coins …

The withdrawn type 2011 Aquatic themed Olympic 50p.

Not strictly errors in the sense that something went wrong during production, but certainly a type of coin that probably shouldn’t have been produced and is often quite valuable. Withdrawn coins are coins with designs that for some reason were produced (often in low numbers), then changed or modified for the rest of the production run. The best known example of a recent withdrawn UK coin is the 2011 Aquatics Olympics 50p – very early coins sold in packages featured a very different reverse with extra lines on the swimmer’s face. This was changed and most of the coins sold in packs and all of the coins that were circulated featured a distinctly different design with less wave lines on the swimmer.

Another example of a withdrawn coin is a recent Falkland Isles 1oz bullion coin produced by the Pobjoy mint. This coin was withdrawn because the Royal Mint took issue with it having the word ‘BRITANNIA’ on it. They pointed out that no one apart from the Royal Mint is legally permitted to produce a silver coin featuring the word ‘BRITANNIA’. Pobjoy had to change it and released another version that completely omitted all wording on the reverse.

22. Brockages …

A brockage is a very rare type of error that is observed occasionally on older coins. I’m not aware of any clear modern decimal brockages. A brockage occurs when a coin is struck normally, somehow adheres to one of the dies and fails to eject. The next blank planchet is inserted and struck with the normal die on one side and with the coin that previously failed to eject on the other! The result is a coin (brockage) which is normal on one side and has an incuse weaker version of the same design on the other side.

The coin that originally got stuck in the die and failed to eject is known as a ‘die cap’ error. These are usually very expanded, a bit like a broadstrike (see also no.5B) with an irregular shape. Die cap errors are very rare.

A 2002 UK territory 50p die cap error.

23. Double sided coins (often 1960s and shouldn’t be possible) …

Coins that are ‘double headed’ or ‘double tailed’ shouldn’t exist, at least not accidentally. The setup should make it impossible for the dies to physically be put in the wrong place. In almost all cases, doubled-sided coins with the same design on both sides have been created by manipulating two coins.

I have never personally examined a genuine double-sided decimal coin. I am aware that my predecessor at Rotographic did list a couple in previous editions of the book upon which this website was originally based. The coins in question were from the late 1960’s or very early 1970’s and were most likely created deliberately by Royal Mint employees to test out dies or some other element of production. A few double sided coins were featured in the Joanna Tansley collection, sold in 2005.

24. Mules (human error) …

A mule is simply a coin struck from a mis-match of obverse and reverse dies, dies that should never have been used together but were incorrectly set up due to human error. There are a few modern well-known UK mule coins. The best known is probably the 1983 NEW PENCE 2p, made using the incorrect reverse die. Very well known and also quite common (for a mule) is the dateless 20p, which was made in 2008 as a result of someone using the incorrect obverse die from the previous 20p type. A more recent mule and so far very rare is the 2016 new £1 coin where the incorrect reverse die was used with ‘2017’ micro dates around the edge.

There are other mules including a 1994 gold proof £2 and a recent mix up with the dies for Lunar and Britannia silver bullion issues. The Isle of Man 1980 Christmas 50p with the incorrect obverse die that doesn’t state ‘Isle of Man’ is a known non Royal Mint mule. Not all mules are incredibly valuable, as the usual demand and scarcity factors play a large role in obtainable prices.

25. Struck off-centre …

Both sides of a very off-centre 2017 £1 coin.

Occasionally coins are seen that have been struck slightly off centre due to mis-aligned dies, evident from an uneven rim with a thicker section on one coin side. Such coins aren’t usually of high value (it does depend on severity, as with all error coins). Coins that are struck very off-centre with missing detail on both sides are considerably rarer and are caused by the planchet being mis-aligned within the dies, rather than just a slight mis-alignment of one die. They often look spectacular enough to whet the appetite of many error collectors and for that reason tend to be of higher value.

Note that error coins known as ‘broadstrikes’ (see 5B) can also appear not properly centred.

26. Struck on wrong planchet …

My own personal favourite and the type of error that I seem to be drawn to the most! A coin struck on the wrong planchet. It happens when a planchet prepared for a completely different coin, (or in the case of some bi-metallic coins – an incompletely processed planchet) ends up somewhere it shouldn’t be and is made into a coin. Bi-metallic coins (the £1 and £2) are potentially more susceptible to being struck on a wrong planchet as the manufacturing procedure is more complicated and where there are more stages, there is more potential for something to go wrong.

Bi-metallic coins are by nature, made of two pieces of metal. A pill shaped central disc and a larger ring shaped piece are forced together at the same time as being struck with the dies. On rare occasions a ring shaped brass piece misses out on having a hole punched in it and manages to find its way in with the other correctly holed brass rings. I don’t know exactly how it happens or why the machines don’t notice that something isn’t right when an un-holed brass piece is rapidly inserted ready to be struck, but somehow it does sometimes happen and the result is a £2 or £1 coin made of a single piece of metal.

Bi-metallic coins struck for BU sets and packages are known to be forced together before they are struck. Perhaps monometallic error £1 and £2 error coins are all coins that were destined to become ‘BU’ or proof coins.

Other types of ‘off-metal strikes’ as they are sometimes known, are the result of a completely different blank intended for a different coin ending up somewhere it shouldn’t be and being struck with incorrect dies to what it was originally supposed to become. These incorrect planchets (or planchets in the wrong place at the wrong time!) are often other types of UK coins. The Royal Mint also strike coins under contract for many other countries. It’s very rare but can happen that ‘foreign’ blanks end up in the wrong machinery and get struck as UK coins.

Other factors can result in coins that look like they have been struck on wrong planchets – very stained or corroded coins (e.g. due the coin being previously buried underground) can sometimes appear to be a completely different colour/metal and can be mistaken for a coin on a wrong planchet. Also, 1p and 2p coins that are silver coloured are often normal coins that are missing their copper plating, see no. 11. Coins that have been manipulated and plated with another metal can also resemble a wrong planchet coin. Sometimes careful analysis is required.

Here are examples of coins struck on wrong planchets:

A 2015 technology £2 coin on an all-brass (un-holed outer disc) planchet.


A 2008 50p struck on what appears to be (from the weight and magnetic properties) a one penny planchet.


A 2010 Florence Nightingale £2 struck on a foreign planchet (made of nickel plated steel). Most likely one intended for a Gambian 50 Bututs.

27. Mixed denominations …

An incredibly rare type of error coin where a number of mishaps have occurred in the production process. These are the result of an already finished coin being processed once more as another or part of another (different denomination) coin. Resulting in a concoction that incorporates elements of two completely different denominations. The examples described here are both mixtures of a £2 coin and a 50p from the same year.

The example shown below has been confirmed as such an error by the US grading service PCGS. What appears to have happened is that a finished normal 50p (the 2006 VC cross heroic acts coin) has somehow ended up with the round brass discs that are normally holed to eventually make up the ring part of, in this case, the 2006 Isambard Kingdom Brunel £2 coin. The finished 50p has been holed along with the other brass discs and has moved along regular £2 production then been struck and combined with a regular pill shaped inner silver part. As the 50p outer ring is slightly thinner than a £2 coin, it doesn’t show much of the £2 detail and still clearly shows ‘FIFTY PENCE’ from its previous existence as a regular 50p.

A 2006 £2 coin struck with an outer ring made from a finished 2006 50p.

The PCGS website image of the same 2006 £2/50p mix coin.

The other known combination of an outer ring made from a 50p with a £2 centre is a 2014 coin. It features the centre £2 part of the Lord Kitchener coin and the outer ring from a standard shield-back 50p.

Authentication of UK error coins …

This is not an error! This is the result of someone squashing two 10p coins together with a lot of force. The incuse ‘tails’ detail on this coin’s obverse was made by another coin.

With man-made fake errors being common for certain coin types (the bi-metallic £1 and to a lesser degree, the £2). And with Chinese forgeries of error coins also known to exist it’s understandable that some collectors seek official confirmation. The Royal Mint do very kindly examine your UK error coins, for a small fee, and return them with correspondence describing the error (if the coin is a genuine error). Sometimes the letters can be very generic and do not go into any detail about the error type.

This is all very well, but is unfortunately open to abuse for two reasons. 1: The coin that the letter relates to is not photographed, so theoretically the error coin that the Royal Mint examined could be swapped. And 2: The letters are on Royal Mint headed paper, but are fairly easy to replicate. In fact I’ve seen a fake letter claiming to be from the Royal Mint describing a very dubious looking error coin. In a similar fashion, screen shots or print-outs of emails can also be faked!

The Royal Mint have some highly experienced coin experts and have a lot of expensive equipment. However, the letters they return are written by humans and they are not infallible. I’ve seen the text of a Royal Mint letter regarding a suspected error coin submitted by someone in 2015, where the coin in question had been, according to the Royal Mint, plated in nickel by someone post-mint. This was a conclusion that I did not agree with based on other factors, including the weight of the coin and other evidence relating to its appearance. Even experienced error collectors don’t always agree!

In the USA

The error coin industry in the United States is massive in comparison to the UK. An alternative to authenticating errors via the Royal Mint is to send coins to one of the US grading services. The top two US grading services have very high standards with regards to authenticating and grading coins. These companies charge a higher fee for encapsulating (or ‘slabbing’) coins, so it’s best to only submit coins for which you are 100% confident of them being a genuine error. Encapsulated coins are guaranteed. If you buy any ‘slabbed’ coin and can prove that it is not as described on the label then the grading company can be made liable for its cost. When buying slabbed coins check the number and images online. There are known Chinese made fakes of coins in slabs!

As a general rule, serious collectors of UK error coins tend to have a very good understanding of the minting process. With a combination of that and the experience gained from seeing or studying similar error coins, they can usually identify a genuine error coin. Error collectors will often trade with each other without the need of any kind of official authentication. Trusting instead their own instinct and experience over above and beyond the knowledge of others.

Thank-you for reading this, any typos or other suggestions, let me know.

by CHP 16/12/17. Slight changes made 2/9/18. With some corrections/additional information by Jason Renaud and some proof-reading by Laura Davis, Sarah Grant and Candice Clews.


The Check Your Change admin is Mr C H Perkins, publisher of numismatic publications in printed and eBook format. Author of "Collectors' Coins - Decimal Issues of the UK" and other books on British coins and related subjects.


  1. A. Warren
    11th February 2018

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    Is the £2 coin I have rare or common?
    The inner part has a piece cut off?

    • CYC-Admin
      13th February 2018

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      I’d need to see it, but it’s likely someone has pushed the middle out, removed a piece and then pushed it back in again.

  2. paula siddall
    16th April 2018

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    How mthinkmytrial1youuch do you think my trial pound coin is wearth with date 2016 on iii when I was reading just then and it said only around 20 up to now have been found not as many as 30ihope it is yes I just happened to check earlier also I have got a hammered medieval coin yay’. It is very clear left facing king I think its either Henry the 8th or Henry b4 him is pops. Or even his son who was very young at this time I’m sure that Henry8ths face was left on coins after death which was again a deliberate error Henry is my all time best ever KIng .

    • CYC-Admin
      3rd May 2018

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      You’re sure it’s the 2016 trial £1 coin, with the ‘TRIAL’ reverse? I don’t know the exact numbers made or available yet. I can’t comment on your hammered coin, it’s too old for here!

  3. Derek Munro
    25th April 2018

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    I have a new 2016 pound coin with the queens head on both sides .

    • CYC-Admin
      3rd May 2018

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      I suspect it’s been messed around with by someone! Send pics if you like.

  4. Cris lee
    19th May 2018

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    I have a 50p coin without a date is this unusual

  5. C lee
    19th May 2018

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    Do not know how to fill in your form. What website do you require I am a complete technophobe

    • CYC-Admin
      20th May 2018

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      That’s ok, it’s a bit of a pointless field for most people! ‘Website’ is where you put your own website, if you have one. If not, just leave blank.

  6. Mike
    25th May 2018

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    i good friend has a £1 coin where the milling around the edge is a full rotation out. if you line it up with a pile of other £1 coins, the smooth bit lines up with the milled part and vice versa. We’ve tested it against 50+ other £1 coins and its the only one we have seen with this milling error.

    Is this a significant error or are their loads out there?

  7. sabeena
    27th June 2018

    Leave a Reply

    I have a 2p coin that looks like the queens face is damaged like a hole in her face looks kind of burnt but just the face part . Your thoughts? 1996 2p

  8. David jones
    25th August 2018

    Leave a Reply

    I have a one pound coin that says on bottom test piece ?

  9. ken hawkins
    4th October 2018

    Leave a Reply

    I have two 1996 5pence coins,one is normal,the other one’s 6 looks bent to the right and the top tail part is more elongulated,am curious to know if it could be classed as a rare mistake in the production process,it is unusual compared to the normal 5p,is it valuable to collectors of such coins,am not interested in selling it,i would just like to know if its rare and unique in the coin world,once i find a way to properly photograph it up close,i will send you the pictures

    • CYC-Admin
      4th October 2018

      Leave a Reply

      Whatever the cause, it’s likely to be something fairly minor, but I can’t really speculate without seeing pictures.

  10. Bonnie
    16th November 2018

    Leave a Reply

    I have 1987 1 pound Elizabeth Ii
    Doubling face of Elizabeth this rare error?

  11. Shaun
    24th June 2019

    Leave a Reply

    I have 5pence coin 2017 has a small queen head and 2014 has a big queen head

    • CYC-Admin
      24th June 2019

      Leave a Reply

      The portrait of the Queen was changed during 2015, which explains the difference.

  12. Leony
    2nd July 2019

    Leave a Reply

    I have a 2017 £1 coin with a centre peice that rotates? Is this normal?

    • CYC-Admin
      3rd July 2019

      Leave a Reply

      It’s not normal, but it’s likely someone has messed around with it. With the right tools it’s possible to push the middle out. Perhaps someone did that and then pushed it back in.

  13. Graham
    6th July 2019

    Leave a Reply

    I have a 1976 10pence coin, which has been sent and returned from the royal mint, with a letter saying it had been struck on an Brunei placnchet, it weights 9.4 grams, is this coin a of any value!!

  14. Kate
    16th July 2019

    Leave a Reply

    I have a two pound coin, that looks like the middle is completely reversed, is that an error? meaning the gold bit that says two pounds and the date are with the queens face rather than the pattern, kate

    • CYC-Admin
      25th July 2019

      Leave a Reply

      It sounds like someone has used force to push the middle out, and then put it back in the wrong way (deliberately probably). Some people try it on with those on ebay, describing them as an error.

  15. Steven Hardcastle
    12th October 2019

    Leave a Reply

    Very interesting and useful, perhaps the Royal Mint should take us back to the coin checking days of the sixties.

  16. Linda
    13th October 2019

    Leave a Reply

    Hi I have 2 20p 2011 coins that have a few errors front and reverse and would like to know the reason for this. The queens head is also slightly different.

    Can you advise?



    • CYC-Admin
      22nd October 2019

      Leave a Reply

      I got your email, thanks. It looks like the problems were due to die deterioration.

  17. CN
    23rd November 2019

    Leave a Reply

    Hi, I have a £2 coin with 1607-2007 printed with the 7 printed the wrong way round…is it supposed to be like this or is it an error? Thanks

  18. Karen
    26th November 2019

    Leave a Reply

    Hi, I have a 2913 £2 COIN where the edge is a lot more prominent on one side. Is this unusual?

    • CYC-Admin
      27th November 2019

      Leave a Reply

      Thanks, but not really sure what you mean without seeing pictures.

  19. Nicholas gribbin
    13th December 2019

    Leave a Reply

    I have two. 1 pound coin in side of the queen the silver part look’s as though its been one has been stampt around the queen forehead and stops by her nose the other pound coin looks like a silhouette around face crown and neck plus at the bottom of her neck on two of them the stamp can be seen but not much thanks. very much can i send you a photo of them pls

    • CYC-Admin
      13th December 2019

      Leave a Reply

      That sounds like something that is caused by die degradation, I.e. too many coins were struck with the same die and as the dies get old they get damaged on especially on the new £1 coins that often leads to a raised outline around the Queen and other blobs and unsightly things.

  20. Leonard white
    27th January 2020

    Leave a Reply

    Hi, I have a 2007 5p coin with ‘2007’ stamp reverse orientation to the normal. Is this unusual.

    • CYC-Admin
      27th January 2020

      Leave a Reply

      Yes, but there could be a logical explanation for it. I’d need to see pictures.

  21. John-Paul Lewis
    26th February 2020

    Leave a Reply

    I was reading quite intensely about all your fault coins from the Royal Mint and was wondering about faults, discrepancies on foreign coins, is there somewhere you can find out about rare faults on some foreign coins?
    I have a 1935 French coin that has a very lifted blob of extra silver on the surface. Can this be classed as an extra rare coin in its own right? Don’t believe there would be another like it anywhere. I can send photo if it helps with any answers.

    • CYC-Admin
      27th February 2020

      Leave a Reply

      Generally, as all coins are pretty much made the same way, they tend to have the same sort of errors. There are also things that can be done to coins intentionally or by accident, that can also look like errors at first. Yes, send me pictures of it.

  22. Orlaith
    18th February 2021

    Leave a Reply

    I have an old £1 coin with no side lettering. Could this be worth any value?

    • CYC-Admin
      24th February 2021

      Leave a Reply

      I’d need more details and to see pictures. A few don’t have edge words and the details are often very weak on fake £1’s.

  23. F.Tamplin
    26th February 2021

    Leave a Reply

    i have 2 2p 2014 coins which seem to show the queens head with a horn at the front of her head.The royal mint said it was probably a cracked die.Are they worth anything to a collector.

    • CYC-Admin
      26th February 2021

      Leave a Reply

      Without seeing pictures, the most common thing to cause that is probably corrosion of the steel core under the copper layer.

  24. alexander creasey
    13th April 2021

    Leave a Reply

    Hi, I have a guy fawkes £2 but it appears to have a few flaws stars merging, the 5 on 2005 seems to bleed into the silver and the I in the fifth on edge is missing is this a fairly common coin ?

    • CYC-Admin
      13th April 2021

      Leave a Reply

      Sounds like common mass-production problems, little mishaps that often occur (without seeing it of course).

  25. JBrindle
    16th June 2021

    Leave a Reply

    I have a 10p which is silver one side and copper on the other – looks like 2p but is a 10p

    • CYC-Admin
      20th June 2021

      Leave a Reply

      That’s probably due to a problem with the alloy mix (which should be an alloy of copper and nickel – for the older 10ps). There are a couple of different things that can go wrong to make a coin look like that.

  26. Andrew Carter
    5th November 2021

    Leave a Reply

    Hi everyone
    I have a UK 2010 One Penny Piece, that has the reverse side stamped over the Queen’s head side. Which clearly shows the dotted line and harp . I have contacted Royal Mint have confirmed they have no other same coin on their files or physical in there Museum. They have asked me to send the coin too them so calcification can be confirmed. I can’t see it would be worth while for anyone to fake a Penny
    The Royal Mint has not confirmed or stated the 2010 One Penny Coin has errors.
    What l am trying to find out is a common fault on UK Coins.



  27. Roger Lamb
    9th February 2022

    Leave a Reply

    I have a pre-steel 2 pence planchet that was not struck. There is no surface detail at all apart from some dents due to machine handling. I don’t suppose it is worth anything, but I keep it in the cabinet with hundreds of other coins. It weighs the same as a struck coin.

    Also, I am guilty (but I don’t feel guilty) of biffing out the centre of several £1 and £2 coins, but I spent them in the usual way. I took care not to damage the pieces, and reassembled then as closely as I could to the correct rotational orientation, reversed.

    • CYC-Admin
      9th February 2022

      Leave a Reply

      Unstruck planchets like that don’t tend to be worth a huge amount. I bet all of the £1/£2 coins that you reversed ended up on ebay for £1,000,000 each (when it was a no commission bonus day) and are still listed in the ‘unsold’ items section ;).

  28. Amogh
    2nd May 2022

    Leave a Reply

    I have a 2015 twenty p coin with a slightly different colouring to the original can you tell me if it has any value

    • CYC-Admin
      2nd May 2022

      Leave a Reply

      They can quite often appear golden. This is thought to be due to the higher copper content of the 20p (compared to other silver coloured coins) and some kind of minor issue with the alloy or migration of the copper atoms to the surface of the coin. I’m not sure exactly why it happens, but it is fairly common.

  29. Jay
    19th September 2022

    Leave a Reply

    Have a load of 1 and 2p coins from 1971-1981 that say NEW PENNY or NEW PENCE instead of ONE PENNY or TWO PENCE. I have searched online, but it is varying as some sites say that they are extremely common and worth £1.50, if that, and that’s mainly because of the year they are dated to. However, some videos, a few sites and nearly ALL eBay offers list it as a rare thing and that it’s worth over £2000.

    • CYC-Admin
      19th September 2022

      Leave a Reply

      It’s just the 1983 NEW PENCE 2p that is significant and genuinely rare. The others are all face value coins.

  30. paul kennedy
    30th September 2022

    Leave a Reply

    Hi,I think I have found in my change a 2011 £2coin standing on shoulders with a 180 degree dye rotation.I got it weighed and it was the correct weight.I also took it to an auctioneer and he thinks it looks genuine but that still hasn’t reassured me.How do I go about getting it verified from a reputable dealer.

    • CYC-Admin
      30th September 2022

      Leave a Reply

      Die rotations are pretty obvious to see and many aren’t particularly significant (for certain coins/dates they seem fairly common these days). I think most people just sell them privately – the best way is with a photo of the coin in front of a mirror, so the rotation is obvious to potential buyers.

  31. Karen
    1st November 2022

    Leave a Reply


    I have a 2016 army face coin with multiple issues on the coin.

    Royal mint have said it maybe ghosting/die clash but without looking at it properly they can’t say for sure. I sent in pictures.

    The more I look at the coin the more things I see that are unusual about it, feeling more than 1 overall issue (but i am a newbie at this). I received this coin in my shop change last week and don’t know if its a proof coin or not, just know its really shiny new looking for a 2016 coin, with lots of different issues on it.

    Can you help with giving your opinion by taking a look at my photos too?
    P.s. if you can take a look at my photo’s, where do I send them?

    Kind regards

    12th December 2022

    Leave a Reply

    I have a 2010 5p coin the wording five pence across the centre and the P in pence has no whole in the centre of the P it’s filled in, is it worth anything as a print error please?

    • CYC-Admin
      12th December 2022

      Leave a Reply

      Without seeing it I would guess that it’s probably been struck with worn out dies. The letters often appear bloated when that is the case. I wouldn’t imagine it would have any extra value.

  33. Brian Farley
    18th March 2023

    Leave a Reply

    I have a 2002 10p coin with a rounded edge, no milling. Minor wear on faces and edge seem the same, fairly good condition. Just curious, maybe a collector might want it. Any comments?

    • CYC-Admin
      22nd March 2023

      Leave a Reply

      The milling can sometimes be weak, and/or worn off. I’d have to see pics but I wouldn’t imagine it would have much value.

  34. Mike
    24th April 2023

    Leave a Reply

    Whilst metal detecting, I happened to find a 20p that was struck on a foreign blank, it’s the same size as a 5p just a fraction thinner, I took it to my local auction house, to see of what value it could have, and was offered £80 but declined the offer, about two weeks later, I decided to clean the coin in vinegar, as there was some rust, bad idea I know now, and thus removing the lovely brown patina, I was just wondering if it could still have any value.


    • CYC-Admin
      24th April 2023

      Leave a Reply

      Being underground isn’t usually good for any modern base metal coins. Show me some pictures (e.g. over email).

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