FAKE �1 coins are being discovered in wallets and tills across Cambridge.

With one in every 34 thought to be counterfeit, The Royal Mint has warned the number of fake �1 coins is rising.

Its most recent survey found 2.94 per cent of the �1.474 million �1 coins in circulation in the UK are indeed counterfeit currency.

And while shopkeepers and bar and restaurant staff have become accustomed to checking notes for a watermark, it is unlikely a law-abiding member of the public will be any the wiser they have been given a fake �1 coin until they try putting it into a parking meter.

A spokesman for the Royal Mint said: “It’s a problem we take extremely seriously.

“We work closely with the banks and the Post Office to identify and withdraw counterfeits, and also with the Serious and Organised Crime Agency (SOCA).

“We recommend that anyone who receives a fake coin should notify the police or Crimestoppers because if there is a sudden surge of fakes in one area it will be noticed and investigated.

“We recommend that people always check their change when they receive it.

“At that point if they suspect a coin is fake they can refuse to accept it, but if they take it away they can’t go back later and ask for it to be changed.”

If the number of fake coins rises to the point where it affects public confidence, the Treasury could decide to scrap all existing �1 coins and reissue them.

Due to the expense involved, this is a last resort – but one that was used in South Africa in 2004 after businesses increasingly refused to accept the five rand coin.

In Cambridge, however, the realisation of the number of fake �1 coins in circulation – to varying degrees of standard – has simply got residents examining their change more closely.

Antoinette Askin, a pastoral assistant at Our Lady and the English Martyrs, recently discovered a fake �1 coin when it was rejected by a counting machine used at the Catholic church in Hills Road, Cambridge.

She said: “Our local police beat officer suggested that it would be a good idea to show the fake coin and a genuine one to the children who attend classes at the church, to make them aware what they should look out for in case unscrupulous people tried to pass the dud coins onto them.

“I did just that and I have to say they were very sharp and saw the differences immediately.”

A volunteer at the Save the Children shop in Magdalene Street, Cambridge, said she was surprised when a member of staff at NatWest told her she was trying to pay in a fake �1 when doing the shop’s banking.

The volunteer, who asked not to be named, said: “He told me I was �1 short because there was a fake but wouldn’t give it back to me because it would be handling fraudulent currency.

“He showed it to me and it was a bit tarnished but he said the engraving around the circumference of the coin wasn’t right.

“I think we might have been given another one since and it certainly has got me looking at the change more carefully.

“I have warned the other volunteers.”

Andy Campbell, managing director of Stagecoach Cambridgeshire, said he was keeping vigilant after receiving warnings from Stagecoach companies in other parts of the UK who had noticed a rise in the numbers of fake coins they were receiving.

Barkers Bakery in Chesterton Road receives as many as three fakes a week.

Manager Amanda Sanderson said they slip through the net on a busy day.

“You can tell they are fake as they make a different sound if you drop them,” she said.

And Michael Brown from Brookfields in Cambridge said he only realised the coin in his wallet was a fake when successive machines he tried it in kept spitting it out.

Cambridgeshire County Council, which collects the money from the on-street pay-and-display machines around the city, said it was extremely unlikely its machines would accept a fake coin, as proved in a recent audit.

“Out of several thousands of pound coins, the number found to be potentially fake was in single figures,” said a spokesman for the council.

“Our collection machines have a very sophisticated coin mechanism which is designed specifically to detect fake or foreign coins.”

While many people would not like to trouble the police with reports of a fake �1 coin, Cambridgeshire Constabulary said it takes forged money seriously.

A spokesman said: “We would urge anyone who suspects they have been given a forged coin or note to contact us on 101.”