UK banks are to pilot anti-fraud technology which uses text messaging and email to verify credit card purchases.

The service will be tested by banks using Mastercard's Ariston anti-fraud service and is aimed at cutting the £400m bill for card fraud in the UK each year.

If successful up to 20 million credit card holders in the UK will be sent an SMS message to their mobile phone or an email to verify suspect transactions.

The Communicator technology is a plug-in module available for the next version of Ariston and will be tested by Citibank, HFC and Bank of Scotland.

"We are initiating a pilot with Ariston to monitor our debit card portfolio and to broaden our services in this area," said Derek Pak, vice president of fraud risk management in Europe for Citibank.

The Ariston package allows fraud analysts to set rules that will highlight specific patterns, such as a merchant swiping the same card twice within a few minutes.

The device will allow investigators to spot and take action against fraud immediately, according to Mastercard's partner Europay.

François Adant, head of risk prediction services at Europay, said: "The ability to verify a purchase by SMS can be a powerful aid.

"For example, you're a cardholder receiving an alert about a purchase of a diamond ring with your card, but you're thousands of kilometres away, maybe even in another country. The fraud is obvious, the action immediate."

Consumers will not initially be liable for fraudulent transaction alerts they do not respond to, and individual banks will decide whether to send alerts for every card transaction or just suspect ones.