Retailers are being advised to step up security around their Chip and PIN machines after an increase in ‘substitution attacks’ on terminals.

Stores in the Southampton area in particular have been targeted by a scam in which individuals claiming to be engineers remove terminals for servicing. Genuine terminals are then replaced with substitutes, which have been altered to store cardholders’ details.

The fraudsters later return to replace the original machines, taking away the duplicates from which data can be downloaded.

Action Against Business Crime, the joint venture between the Home Office and the British Retail Consortium, is advising retailers to be suspicious of any engineers who turn up without prior arrangement.

Store owners are also advised to carry out checks on Chip and PIN equipment, and particularly the cabling, to ensure it has not been tampered with.