The Royal Mint has confirmed a new kind of error on £1 coins, and if you have one in your change, it could be worth £3,000. The Mint made a mistake when it put the date on them. The coins are stamped on one side with 2016, and on the edge of the reverse - in tiny text - it has 2017.
See also: Only 100 days left to spend your old £1 coins
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The coin was discovered by window cleaner and keen coin fan, Richard Bird from Hull. He applied to have it checked out by the Royal Mint, which confirmed they were aware of the error - but thought that all the affected coins had been removed from circulation.
This should be good news for coin collectors. The fact that the Mint spotted it and tried to remove all the mistakes from circulation means that the error is likely to be rare, which makes the coin more valuable. Bird has had it valued at £3,000. However, the fact that they missed one means there's a good chance they missed others, so it's well worth checking your change.
Other valuable £1 coins
The new error coin is one of the most valuable versions of the £1 coin so far, but it's not the only one. Website Check Your Change has discovered two mistakes that are rare enough to make a £1 coin more valuable to collectors - although they're not worth as much as £3,000.
The second is known as the 'leaked egg' error, because it helps you picture the mistake. If you think of the silver bit in the middle as the yolk and the gold bit around it as the white, it looks like a broken egg, where the yolk has leaked into the white. In extreme cases so much of the silver has leaked into the gold that it has left a gap in the silver on the other side.
The site also warns that there are unscrupulous people trying to create their own errors and cash in - by pushing the middle of the coin out and either manipulating it or putting it back in the wrong way round. These are worth being aware of and avoiding completely. They're not worth any more than £1. In fact, because they have been damaged, they're not even worth £1 any more.