Fraudsters are hiding camera phones in the roofs of cash points and recording the pin numbers of cards surreptitiously trapped in the machines.

Police said several ATMs have been targeted in Wimbledon over the last fortnight.

Last Wednesday two men were arrested next to a cash point in Kingston Road and charged with fraud.

Police are warning cardholders to be aware as fears mount that more people could be caught out by a scam known as a Lebanese loop.

A small loop of plastic wire is inserted into the slot of a cash point and catches cards as they are ejected from the machine.

The owner believes the card has been held by the bank and fails to cancel it before thieves carefully pull the loop and card from the slot and take money from the account.

A camera hidden behind the plastic roof of the cash point records users as they key in their pin numbers, through a small hole in the cover.

Detective Sergeant Norman Laughton, of Merton police, said: “There have been several reports across the Wimbledon area where customers have claimed their cards were not returned. When the banks have checked, they’ve found that the cards are no longer in the machines.”

He added that cardholders should shield the keypad while entering a pin and be aware if anything seems out of the ordinary with the appearance of the machine.

• Iulian Laurus, 19 of Ashbourne Road, Mitcham, and Ionut Mendela, from Harrow, pleaded not guilty to two counts of fraud and one count of theft at Wimbledon Magistrates court on Friday.

The pair were remanded in custody and are due to appear before magistrates today.