A hard core of Bradford villains are involved in a crime wave which sees £1million-worth of cars stolen a week in West Yorkshire.

Gangs of 'Hanoi' burglars, who break into houses for keys to steal cars, have become so prolific that police have set up a specialist team to tackle them.

A spokesman for the Operation Hanoi team, set up at Pudsey police station, said a lot of the people committing the crimes lived in Bradford.

"There is a hard core of about ten people from the Bradford area travelling out of their patches to commit these crimes," he said.

"At the moment there are in the region of 50 Hanoi burglaries a week committed across the force."

Cars being targeted are Audis, BMWs - especially the X5 model - VW Golfs and Passats and Peugeots. Their value ranges from around £12,000 to £50,000, with the average being between £20,000 and £25,000, meaning that at least £1million-worth of cars are being stolen in the county every week.

Last week the Telegraph & Argus revealed that Hanoi burglars had committed ten offences in just two days in Guiseley and Otley.

BMWs, Audis and VW Golfs were among the top-of-the-range vehicles stolen in the spree by a team hunting for particular types of car.

And this month police warned about a gang who carried out raids using a bamboo cane to hook car keys through letterboxes. They struck three times in one night across Bradford.

Police say a couple of gangs of car handlers had received considerable prison sentences last year but the problem was on the increase again as more gangs took their place.

"There are several teams involved, some are better and more prolific than others," said the spokesman.

Last July five Bradford men were jailed for nearly 25 years for their part in a £60 million car crime spree that, at its height, saw nearly 300 Hanoi burglaries committed in one month across West and North Yorkshire.

In September another five Bradford men were sentenced to more than 11 years for receiving cars stolen in burglaries and robberies.

And in October brothers Ishtiaq and Israr Zahir were both jailed for three and a half years for running a car-ringing scam from their Manningham breakers yard which processed £400,000-worth of vehicles stolen in Hanoi burglaries.

Police are urging householders and car owners to be more security conscious - locking back doors and not leaving car keys in view.

The spokesman said: "A lot of these crimes are sneak-in burglaries and a majority of them have happened when the householders have left their doors unlocked.

"We have done a lot of publicity and leafleting of homes to try and get the message across about home security, but it is amazing how many people still leave their homes insecure.

"Perhaps they don't think it will affect them. It is a problem people need to be aware of."

The team is trying to combat the burglaries by giving the public crime prevention advice and by targeting and identifying those they suspect of committing the crimes.

The spokesman said: "Information from the public is important to help us catch these criminals and we are getting some information. We are hopeful of increasing public awareness of the problem so those responsible are caught."