It will be introduced by 2017 and the Royal Mint has claimed that it will be the “most secure coin in the world”.

The design for the new £1 coin has also been likened to the old threepenny bit, with its 12 sides.

But it will cause headaches at Mr P’s Classic Amusements in High Street, Gravesend, which has 78 slot machines, some dating back more than 20 years.

Owner Amelia Douglas, 23, said that although the coin would be good to combat fraudsters it would cause havoc with her machines and cost her hundreds.

She said: “It is going to cost us a lot to change all the mixes and tubes inside the machines. It’s not good, really.”

“We’re probably looking at about £50-£60 on each machine depending on what it does need.

“It’s a nightmare, especially with the switchover, because we’re going to have to make them accept the old and the new coins.”

Barry Smith, owner of Cointron, in New Road, said that the change would cause only slight problems.

He said: “I think it will be about £25 per machine but it will be nuisance.

“Hopefully the coin mixers in the machines will be able to take the old and the new coins at the same time.”