A new report claims there are an incredible 50 million fake £1 coins in circulation. This is up 6 million since we last reported on it in April 2012. The Treasury is doing its best to crack down on the fakes, and has removed 9 million from circulation in the past five years - but it's a losing battle.
The report in the Daily Mail warns that one in thirty pound coins are fakes, so there's every chance you have been handed one in your change, and you could be carrying one now.
In March last year, Dutch police found a mint in Amsterdam, which was capable of producing hundreds of convincing fake pound coins every minute. At the time, reports claimed the operation had been going for at least eight years, during which time they had produced around £4 million worth of coins each year.
It was partly as a result of this discovery that the Treasury decided to replace the £1 coin with something that's harder to fake. The coin will have 12 sides and be made of two different metals - which will make it far harder to copy. The Treasury is claiming that it will be the most secure coin in the world.
This will enter circulation in 2017, but in the interim it's worth taking a bit of time to understand how to spot a fake.
The Royal Mint says there are some common issues with fakes. The design on the back of the coin is changed every year, the inscription on the side is changed at regular intervals, and the Queen's head is changed too. On some fakes, the date and the design don't match. The Royal Mint has a list here of the correct combinations, so check yours are right.
There are also some quality issues with the designs on some of the fakes, so the ridges on the edge of the coin are not clearly defined, the lettering may be uneven in depth or spaced oddly. The designs may not be as sharp as the real thing either.
The front and reverse may not match up: if the Queen is facing directly downwards, you should be able to spin the coin and see the design on the reverse is facing in exactly the same direction. If it doesn't, it's a fake.
There are problems with the metal of some fakes too. In some cases it's simply the wrong colour; in others the date of the coin will show it has been in circulation for some time, but the coin will show no signs of age.
If you think you have a fake, you should hand it into a local police station so it can be withdrawn from circulation - simply spending it and passing the problem to someone else is illegal. The problem, of course, is that you won't get any money back after handing your coin in, so it may put some people off doing the right thing.
It means the most sensible approach is to check your change carefully, so you don't end up accepting any fakes in the first place.
Coins on AOL Money
'Schoolboy error' on new £2 coin
Man cashes in 500lbs of pennies
The most expensive one-cent coin of all time: £1.55 million