Originally thought to be a one-off, but now more have come to light since this post was originally written in September 2016.
This is a newly discovered 2015 Britannia £2 coin error that concerns die alignment. Normally all modern British coins are aligned such that the when turned on a vertical axis (finger and thumb at the top and bottom of the Queen) the reverse should also be the right way up, i.e. Britannia’s head should be at the top in the 12 O’clock position. This is what numismatists call medal alignment.
For a few 2015 Britannia coins (and possibly a lot more) one of the dies has rotated resulting in incorrect alignment. When the ‘heads’ side is held at the top and bottom and the coin is rotated, Britannia’s head is facing towards about 4 O’clock, and is therefore out by about 100 degrees. Another has been seen which is almost upside-down, i.e. more than 100 degrees. Such errors shouldn’t be possible as the Royal Mint fix the dies in position and they shouldn’t be physically able to rotate.
The only way to photograph both sides at once, and the only way I can confirm another discovery is to take a picture in front of a mirror, like this:
This error was first confirmed by checkyourchange.co.uk in September 2016. If you have one of these die alignment error £2 coins, please let me know.
Collectability/Scarcity: 5 (for scale details see here)
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.