2017 Single Metal Error £1, the Facts

By on 31st January 2018

The monometallic error £1 coins and my BU set theory

Noted in the press recently (the Times first reported it on 30/1/18) there has been some exposure for the discovery and forthcoming auction of a 2017 £1 coin made of a single piece of golden brass coloured alloy.

About 10 or more of these error £1 coins are known to me and I examined one in the flesh just after Christmas 2017. Despite what it said in the press and on certain websites, I’m convinced the coins have not been struck on old pre-2016 single metal blanks, as for that to be the case, the weight of them would be – within a gnat’s whisker – about the same as the older round pound coins – and it isn’t, it’s not even close. The claim that an old round pound blank was stuck in the machinery for months or years is also very unlikely indeed.

Another single metal 2017 £1 coin (sorry about the poor lighting).

The monometallic £1 coin I examined weighs 8.70g, which is exactly in line with the normal weight range of the new 12 sided £1 coin. Old £1 coins were heavier, at about 9.5g. The circumstances that have led to these error coins is in my opinion due to a brass piece intended to make up the outer ring-piece failing to have a hole punched into it and somehow being struck as a coin, without the intervention of any nickel plated centre pill-shaped piece, which would normally be introduced and pressed into the brass coloured ring by the dies*, at the same time as the coin is struck with the design. A number of £2 coins for which this error has also occurred are also known and have been examined (see my introduction to error coins post) and the same kind of errors are also known concerning foreign bi-metallic coins.

Despite the incorrect information found elsewhere, this particular mono-metallic coin does indeed seem to be extremely rare. It is a very recent coin though, so potentially more will come to light – especially now that people are aware of them and will look more closely.

See here for my guide on the many new £1 coin varieties plus a couple of more common errors.

* Or not, as in the case of coins that are destined for BU sets – bi-metallic ‘BU’ coins actually have their two pieces pushed together before they are struck. It is therefore quite likely that the single metal 2017 error £1 coins were actually destined to end up as coins in the 2017 BU sets.

Only one 2016 dated mono-metallic new £1 coin, all in brass is known to me. No 2016 new £1 coins were made for BU sets or packages.

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. Mark Rich
    16th August 2018

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    Hi. I have one of these single colour coins and was wondering what happened to the one that went to auction. also where can I get it appraised.
    Thanks Mark

    • CYC-Admin
      16th August 2018

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      Send me some pics and I’ll have a look. The one at auction (described wrongly) went for a silly amount – £2300 after fees! But I know that privately between coin folk they have changed hands before that auction and since for substantially less, like around £300 – £400, but it’s always down to what the next person wants to pay. In the future condition should play more of a role and the nicest and closest to perfect coins will probably attract a decent premium.

  2. SQ
    4th October 2022

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    Hi, I know this is an old post now, but only just found this info. I have a 2016 mono metallic new £1 coin. I originally h ad it in my change back in 2017 and thought it was odd, so I put in a draw and completely forgot about it until now. I do remember searching the internet at the time and could find no info at all!

    I am curious now as your final statement was that only 1 of these 2016 were known to you.

    Is this really as rare as that? I would be grateful for any info you could provide. And yes I am curious as to it’s value.

    Thanks in advance

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