Police are urging people to tighten their computer security to stop internet fraudsters stealing their identity and fleecing their bank accounts.

Identity fraud is one of the fastest growing crimes in Britain, costing millions of pounds a year, and there are thought to be thousands of victims in West Yorkshire.

The Economic Crime Unit of West Yorkshire Police has a dedicated team which works with the financial industry to tackle the escalating problem.

Detective Sergeant Charlie Mann, from the ECU, warned the public that they needed to be more vigilant as applications for banking facilities moved towards phone and online transactions.

"If people are a bit careless with personal details, like utility bills or bank statements, it is lucrative information for thieves," he said. "The message needs to go out to people that it is happening and is on the increase and you have got to be vigilant to avoid becoming a victim."

Identity fraud comes under three categories - application fraud, where criminals get someone's personal details to apply for credit cards or bank accounts under the assumed name; account take-over, where the villain tries to divert money from an existing account; or assuming an identity by obtaining passport or national insurance details.

Last year plastic card fraud cost the UK more than £500m, an increase of 20 per cent on the previous year. Identity fraud accounted for £36.9m of that, a rise of 22 per cent. The Yorkshire and Humber region saw plastic card fraud go up 31 per cent to £20.2m.

And while fraudulent applications, after obtaining someone's details, was down by 14 per cent nationally, the diversion of funds from an existing account soared by 59 per cent.

DS Mann said one of the scams modern-day villains were using was to post spoof banking sites on the internet.

He said: "The customer accesses it, believing it to be genuine, and passes on their bank details, which the criminal then uses to take out money. The way to avoid it is to get the right software package which prevents spam mail."

Another method is cold calling where fraudsters ring up and pretend to be from a bank and purporting to be upgrading security systems to get personal details out of people.

DS Mann said: "No bank will ever cold call anybody. But it is amazing the number of people who respond and provide valuable data."

Fraud lawyer Steven Philippsohn said: "It only takes simple information, such as date of birth, address, a mother's maiden name and passwords, to conduct this kind of fraud.

"However, it falls to the victim to establish that a fraudster is responsible for any substantial debt, and this can take up to 300 hours of telephone calls."