Providing an early warning system, the service will alert Capital One cardholders by email to any key changes on their credit file. The alert includes details of any applications for credit that may have been made in their name with or without their knowledge. The service, provided by Equifax, one of the UK's leading credit reference agencies, is free and available to all Capital One customers - all they need to do is register online.

In addition to the email alert service, Capital One customers will also receive two free full credit reports each year of their subscription to the service.

Srini Gopalan, UK Senior Vice President of Capital One, said: "We recognise that, although the issue of ID theft is serious, customers don't always have time to regularly check their credit file for unusual activity that might suggest they have been victim to this crime. This new ID alert service gives additional reassurance for our customers and makes our ID theft protection service even more robust and valuable. ID theft is one of the UK's fastest growing crimes so this new, forward thinking service will help our customers protect both their identity and their financial reputation and help them solve any arising problems."

The announcement follows research carried out earlier this year by Capital One* that revealed over 42 million adults** in the UK don't know how to discover if they have been a victim of ID theft, while only one in ten knows exactly what do if they suspect their ID has been stolen.

By obtaining somebody's personal details an ID fraudster can apply for credit cards, loans and other financial products or obtain mobile phone contracts in their name. The unpaid debts subsequently accrued are then lodged in the innocent person's name. Ultimately, this can lead to encounters with debt collectors, court actions and problems getting a mortgage or even a job.

The new Identity Alert service adds to Capital One's existing security measures - including offering advice to help prevent, spot and resolve identity theft and a named adviser to provide confidential help at every stage of the resolution process if a cardholder discovers they have been a victim of ID Theft.

*Research conducted by YouGov of a representative sample of 2331 GB adults between 31st May and 4th June 2007.

**Based on population stats from ONS and census data