Police are targeting a black market trade in stolen power tools after a spate of thefts across Oxford.

About 90 power tools - believed to have been stolen - were seized from a trader during a recent car boot sale at Oxford's Kassam Stadium.

The discovery followed about 30 thefts from vans in Blackbird Leys, Cowley and Rose Hill in just four weeks.

Dc Claire Routledge said: "We will continue with this operation and advise car boot goers to be wary of persons selling tools at such venues - they may be assisting in the cycle of theft and distribution.

"It is about supply and demand, if we can make it harder for the thieves and handlers to sell the tools then we should therefore see a decline in theft."

Police raided a stall at Big Ben's Car Boot Sale on Sunday, March 9, and found about 90 power tools.

A van was seized and a 22-year-old man was arrested and bailed pending further inquiries.

The spate of thefts happened during February.

Vans were broken into in Rose Hill, Temple Cowley, Blackbird Leys, Garsington Road and the Fern Hill Road area of Cowley.

The majority of the incidents involved thefts of valuable power tools and copper piping.

Police do not want to reveal the full list sites where tools were stolen, fearing other thieves could be tempted.

Officers are now advising people to remove tools from their vehicles overnight to stop the black market trade.

Vehicles should be parked on driveways and under lights if possible. Police also advise marking and keeping a record of tools in case officers retrieve stolen goods.

The Kassam Stadium car boot sale, which is held every Sunday, has been the target for a series of raids by police and trading standards officers in recent years.

Between the summer of 2006 and March last year, police raided stalls four times and seized more than 2,000 counterfeit DVDs and CDs and thousands of pounds worth of fake clothing.

Hassan Ehsan, 30, of Leytonstone in London, was later fined £300 for five counts of possessing goods with a false trademark.

Anyone with information about power tool thefts or who has been offered cut-price tools should call police on 08458 505505, Crimestoppers on 0800 555111, or Oxfordshire Trading Standards on 0845 051 0845.