Police have warned motorists to be on their guard after a BMW was stolen and a gang were seen “acting suspiciously” by a nearby Audi.

Burglars stole car keys from a house in Cranesbill Drive, Bicester, and drove off in a BMW sports car parked on the driveway.

The thieves struck on Tuesday after the front door of the house was left unlocked.

The car, a grey BMW 530 diesel sport – reg N40 SDM, was stolen between 6.30pm and 7.05pm.

Dc Mark Personius said a group of four or five men were also seen in the early hours on Thursday, acting suspiciously around a black Audi in nearby Lucerne Avenue. He appealed for anyone with information to call him on 08458 505505 or Crimestoppers on 0800 555111.