A charity worker suspects he has been given a fake new £1 coin - despite claims it is nearly impossible to copy.
The new 12-sided piece only came into circulation last month with the Royal Mint proudly announcing it was “forgery proof” and the world’s most secure coin.
But Roy Wright, 48, is convinced he has already stumbled across a counterfeit.
He says the fake, stamped 2016, came in change from a Co-Op in Addlestone, Surrey and has subtle but significant differences to the real thing.
It is heavier, the Queen’s head is more to the left, the edge is more rounded, it doesn’t have a hologram and there is no detail on the head of the thistle.
The new coin is meant to feature a hologram at the bottom which shows a £ symbol and the number one depending on the light.
There is also a secret high-security feature built into the coin designed to protect it from counterfeiting.
Hundreds of “trial piece” coins were given to retailers to help calibrate or upgrade coin-handling equipment ahead of the real coin’s introduction on March 28.
They are not legal tender and cannot be used in shops - although they are fetching decent prices on eBay.
Wright said the coin was actually given to his partner last Friday when she went to the Co-op to buy a three-line Euromillions lottery ticket which cost £7.50.
She paid with a £20 note and was given £12.50 change - two pound coins, a 50p and £10 note.
Wright, who is a charity worker, said: “She came home and put the ticket and change on the bed. Later we ordered a kebab which cost £16 and had it delivered.
“I always give a tip so I went to pick up the change from the bedside table.
“I have a bedside lamp which casts a different shade to the main light and as the coin passed underneath it in my hands one of the coins looked a different.
“I started looking at it more closely and paid the delivery man with another pound coin I had on me.
“I then compared it against three of the normal pound coins and realised it was completely different. It has a different thickness and is a different colour.
“The coin is completely different and is more rounded around the edge.
“There is clearly space between the engraving lines, it’s a different size, the Queen’s head is to the left, and there is no detail of the head of the thistle - it’s just a blob.
“The stem of the coin has got no detail on it, there are a lot of things wrong with it.”
He added: “If I’ve just found one, how many are there in circulation already? It’s quite worrying. It’s supposed to be the impossible coin.”
The new pounds were introduced amid reports that as many as one in every 30 old pound coins were counterfeit.
The man is keeping the coin for the time being and has got it securely stowed in zip-up pocket in his Nike bag.
The Royal Mint has been contacted for a comment but has not yet responded.