Fourteen bank cards have been stolen across Hertfordshire, due to offences involving ATM fraud.

All 14 of the thefts were identified as having taken place in June, as victims' bank cards were retained by the cash machines.

It has also been reported that cash has later been withdrawn using the stolen cards.

Police now believe a "discreet device" had been placed over the machines' card slots, allowing thieves to steel the cards.

Detective sergeant Mark Fava, of Hertfordshire Police, said: "Following an investigation carried out by experts within the banking industry, it appears that in each of the reported thefts the machines retained the victim’s bank card due to a discreet device which had been placed over the card slot of the machine.

"Initially it was thought that the device was scanning the cards and then transmitting the details and PIN to the offender.

"However, in each case it appears that the offender, or accomplice, has watched the victim input the PIN and then retrieved the trapped card.

"The offender has then later used the stolen card and PIN at another ATM.

"As well as all the usual precautions you take when withdrawing cash, you should always examine the machine before use.

"If anything looks out of place or it has any parts which appear to have been added, do not use it and report your suspicions to the bank.

"If the machine fails to return your card or any cash you have withdrawn, you should contact your bank to inform them and then the police on our non-emergency number 101.”