The police have issued warnings following a spate of cash machine frauds.

The advice to scan areas around ATMs before using them and to be aware of anyone standing close by comes after a teaching assistant narrowly avoided his card being cloned at the Highgate branch of Barclays hole in the wall.

Hussein Ali, from Dartmouth Park Hill, went to withdraw cash at about 8am on Saturday, February 24 when he noticed a man who seemed “out of place” on the opposite side of Highgate High Street.

Just as he was about to enter his PIN number the man appeared a few feet away from him and told him there was a problem with the machine which meant he had to tap in the digits then call the bank for help.

Mr Hussein, 51, then noticed a piece of plastic 5cm by 3cm attached to the card entry point. After removing it he turned to see the man, described as well-dressed, olive-skinned, five feet six inches with short black hair, jump into a car and drive off.

“I could have lost a lot of money that weekend,” Mr Hussein said. “It could have been quite serious.”

But West Hampstead resident Leroy Roberts had his account cleared out after a cashpoint in West End Lane Tesco swallowed his card when he stopped off to get cash to pay for a taxi back to his home in Westbere Road.

Mr Roberts, 32, said: “It’s a sophisticated scam that allows time for the card holder to leave before they arrive and clean out what you have.

“It didn’t seem out of the ordinary because an out of order message came up.

“It’s just sad that this kind of behaviour is creeping its way into West Hampstead,” he added.

The Met also advise people to check if devices have been attached to ATMs and report it to the police and their bank.

A Met spokesman said: “If it doesn’t look or feel right then steer clear and, if possible, go inside the bank where it will be safer. And always keep a regular check on your transactions.”

He urged people to remain vigilant, cover PIN numbers and keep an eye on cards.

He added: “If someone taps you on the shoulder or tries to speak to you, just ignore them. When you have left the ATM, put your card away immediately.

“Not being distracted makes it harder for people to take advantage and less likely that they’ll try to,” he explained.