High street bank Lloyds TSB is writing to thousands of customers to warn them that it might have sent their credit card details to complete strangers.

The mistake happened during a promotion to sell customers insurance against fraud.

Lloyds sent a mailshot to 4,000 of its customers offering the insurance.

The letter included forms already filled in with names, addresses and credit card details.

Unfortunately many of the letters had the personal details of customers living at other addresses.

Human error

The BBC has confirmed that the bank has breached the Data Protection Act.

Lloyds TSB said the mistake was due to human error.

A spokesman said that they would be writing to all customers affected warning them that their credit card security may have been compromised.

They are issuing new cards and are offering to meet any costs resulting from the error.