There are about 45 million fake £1 coins in circulation (approx. 3% of the total) and the Royal Mint has issued guidance on how to spot one of them:
1. The date and design on the reverse do not match (the reverse design is changed each year).
2. The lettering or inscription on the edge of the coin does not correspond to the right year.
3. The milled edge is poorly defined and the lettering is uneven in depth, spacing or is poorly formed. The obverse and reverse designs are not as sharp or well defined.
4. Where the coin should have been in circulation for some time, the colouring appears more shiny and golden and the coin shows no sign of age.
5. The colour of the coin does not match genuine coins.
6. The orientation of the obverse and reverse designs is not in line.
7. The best indication is that the Queen's head and the pattern on the reverse of the coin should both be upright when the coin is turned over. If not -it's a fake.
Best Tip: Fake £1 coins are obviously worthless so if you find one, then simply spend it, otherwise it will cost you £1 if you simply hand it in to the bank.
Also FYI: The new ones, see below and which get launched in 2017, won't fit shopping trolleys or coin slots and so at a cost of £10-£12 per coin slot, it will cost the economy around £20 million to cater for them.