Providers sent out more than 300 million unsolicited credit card cheques last year, a new study has revealed.

Credit card cheques have been criticised as costing more than usual borrowing via plastic and can also have handling charges.

They cost consumers £298 million more in charges and interest than standard credit card purchases, a new report by comparison and switching website uSwitch.com has shown.

Mike Naylor, personal finance expert at the website, expressed concern that the unsolicited cheques show some providers are not committed to responsible lending.

He said the danger is that people already at risk of over-indebtedness are being targeted "and the ‘convenience’ of these cheques, coupled with the manner in which they are marketed by the credit card companies, could push them over the edge".

Statistics compiled by financial advice charity Credit Action show that total personal debt in Britain at the end of September was £1,380 billion.