Criminals can work out the card number, expiry date and security code for a Visa debit or credit card in as little as six seconds using guesswork, researchers have found.

Experts from Newcastle University said it was "frighteningly easy" to do with a laptop and an internet connection.

Fraudsters use a so-called Distributed Guessing Attack to get around security features put in place to stop online fraud, and this may have been the method used in the recent Tesco Bank hack.

Researchers found that the system did not detect cyber criminals making multiple invalid attempts on websites in order to get payment card data.