FRAUDSTERS have been siphoning off millions of pounds from British bank accounts using doctored chip-and-pin machines.
Hundreds of devices in Britain and other countries have been used to copy account details and PINs from credit and debit cards.
They were sent via mobile phone networks to underworld electronic experts in Lahore, Pakistan, before the accounts were drained of cash.
Several corrupted machines are understood to have been found at British branches of Asda and Sainbury's.
The gangs are thought to have infiltrated Chinese factories where the machines are made, doctoring them moments after coming off the production line.
They were then resealed so it was impossible to tell they had been tampered with.
MasterCard has alerted stores to the scam, leading to thousands of chip and pin machines being examined.
The corrupted devices are an extra three to four ounces heavier because of the additional parts they contain.
A MasterCard spokesman said investigative teams had been roaming Europe putting the machines on scales to check they had not been affected.
He added: 'The only other way would be to tear them apart.'
