Thieves targeted a dozen cars in an evening crime spree - sparking fresh warnings about security.

In each case, the thieves smashed a window to get inside the cars, then fled - often with expensive laptops.

All 12 break-ins took place in the Thame area, between 8.40pm and 10pm on Wednesday November 28, a police spokesman said today.

The spree began when six laptops were stolen from cars parked at the Swan Hotel, Upper High Street, and Six Bells, High Street, in Thame.

Police believe the thieves then attacked cars at The Lambert Arms in Aston Rowant and Tiddington before finally ending up at the Welcome Break Services at junction 8a on the M40 at about 10pm.

Det Sgt Dave Muddiman said: "The thieves are breaking side windows, and sometimes the rear windscreen, to get into the cars to take the laptops.

"I'd like to take this opportunity to remind people not to leave valuables in their cars and, if they do, to keep their laptops out of sight.

"I'd like to ask anyone who may have information about a silver Audi A3 or a dark-coloured Ford Focus in the areas where these thefts have occurred to contact police."

Crime Reduction Adviser Julia Wheeler said: "We urge motorists to remove all their valuables, particularly laptops, satellite navigators and money from their vehicles whenever their vehicle is unoccupied.

"Most car criminals are opportunists and are unlikely to break into an empty vehicle. It is also advisable to park in a well lit area and to set the car alarm or immobiliser if the vehicle has one."

Anyone with information should ring police on 08458 505505 or speak anonymously to Crimestoppers on 0800 555 111.