High-powered cars are being stolen by organised gangs who break into homes, stealing ignition keys to ship vehicles overseas.

BMWs, Land Rovers and Audis are among the most popular targets in Oxfordshire.

In some cases, criminals use make-shift hooks to "fish" for keys through letter boxes or cat flaps.

Thames Valley Police Chief Constable Peter Neyroud said: "They are actively seeking opportunities to steal high-powered, high-performance vehicles.

"Some of these vehicles are going from people's driveways into containers. We have recovered vehicles in containers from Bahrain. It is a major organised crime conspiracy."

Between September 1 last year, and the end of February, 28 cars were stolen in break-ins to homes or garages in Oxford alone.

They included five BMWs and two Audi A4s. Two four-wheel drive vehicles were stolen from north Oxford on one February evening.

Although organised gangs are believed responsible for a number of thefts, others were taken by opportunist thieves who abandoned vehicles a short time later. Police emphasise less valuable cars are also stolen.

Det Sgt Vince Gilio, of Oxford police's burglary team, said: "In Oxford, it's quite sporadic. It's probably in the region of one per week.

"The opportunist will take whatever is there, while the joyrider targets an address because there is a nice car in the drive. Then there are individuals who are looking to off-load the vehicles."

There has also been a spate of thefts of mopeds from sheds and garages in Oxford, with 10 taken in the same five-month period.

Sixteen cars were stolen by burglars in the Southern Oxfordshire police area between September and the end of February.

There has also been a spate of about 30 Land Rovers taken from rural locations in the past six months, with some taken in burglaries.

Wantage, Henley, and Thame have been the worst-affected areas.

Dc Mark Crook, of the Southern Oxfordshire burglary team, believed organised criminals were responsible.

In the Northern Oxfordshire area, there were 24 burglaries in which vehicles were taken.

Oxford police crime reduction manager Judith Taylor said: "What is happening is that car manufacturers are making vehicles more secure, so one of the ways criminals can get high-performance vehicles is by stealing the keys.

"People leave their keys downstairs in the kitchen or hallway, where they are visible. We want to encourage people to take their keys upstairs, and put them away out of sight.

"People should put their car in a garage if they have one. Garages tend to be full of bits and pieces and low-value items, but they will leave a £15,000 car on the driveway."

Oxford police's crime reduction officers can be contacted on 01865 335172.

Alternatively, visit www.thamesvalley.police/crimeprevention