Sharp rise in London 'cash claw' fraud
Cases of cash machine fraud, where a device is used to trap money inside the machine, have increased more than 15 fold in London in three months.
So-called "cash claws" are being employed to intercept banknotes at cash machines.
Link, which runs the UK's cash machine network, said it signalled a move from high-tech fraud to cruder methods.
London's Dedicated Cheque and Plastic Crime Unit (DCPCU) said cases were now falling following a series of arrests.
Officers from Scotland Yard and City of London Police both work in the investigative fraud unit, which is funded by the banking industry.
Reported incidents have risen from 150 across the UK in May, to 2,500 in London alone in August, according to figures from Link and the DCPCU.
Det Ch Insp Dave Carter, head of the DCPCU, explained how this type of fraud works.
"The criminal comes along and inserts a device called a cash claw into the cash point machine. They take a transaction of money out to enable them to put the device in," he said.
"They then leave it - it's undetectable, it's behind the guard on the cash drawer in the machine. Then the unsuspecting member of the public comes along, attempts to take some cash out.
"The money then gets trapped by this device in the cash drawer and then prevents them from taking the money out of the machine," he added.
"The machine goes out of service and then the criminal comes along, forces open the drawer using a pair of pliers or a screwdriver, forces the device out of the cash machine, bringing the customer's money with it."
City of London police said the scam was widespread in mainland Europe, but they became alerted to an increasing number of cases in the capital this April.
Det Ch Insp Carter said the scam was a change of tactic, but cases were now falling following a number of arrests.
"Criminals have historically targeted cash point machines by capturing the card itself or trying to skim the card data.
"But because of the success of the measures we and the banks have brought in to counteract that they're now targeting the cash itself," he said.
Graham Mott, spokesman for Link, said the scam was widespread across Europe.
"It's a technique which has been seen all across Europe," he said.
"The same technique has been seen simultaneously in half a dozen different countries. Quite why this is, I'm not sure."
"How they got the information, no-one knows. We're seeing exactly the same thing in France, the Netherlands, Italy, and the devices seen are all identical," he added.
He said that the scam gave thieves an opportunity to work independently,
"The criminal doesn't have to be part of a large organisation - if you're capturing data you've got to work for somebody buying or manufacturing skimming equipment [which] is complex," he said.
"Whereas with these devices they're relatively simple and once the criminal has set up it's almost a one man band - he can keep the cash."
He added that customers should immediately report any banknotes undelivered from cash machines.