As thefts go, a gang of scooter thieves could not have been more brazen. Armed with an angle grinder they calmly halted London’s rush hour traffic and in broad daylight set about stealing BBC cameras fixed to bridges to film the Oxford and Cambridge Boat Race.

On at least two occasions the gang roamed the route of the race targeting £100,000 television cameras attached to scaffolding and trained on the River Thames.

They first struck on Putney Bridge just after 5pm on Thursday, minutes after the Oxford and Cambridge crews had rehearsed the start of the race on the river below. The gang fled empty-handed when challenged by an off duty policeman and a crew from the Royal National Lifeboat Institution.

The thieves then drove to Barnes Bridge where they outnumbered BBC security staff and cut down a BBC camera fixed to scaffolding. The gang fled and remains at large.

Rowena Chowdrey, a professional photographer who took photographs of the thieves on Putney Bridge, said she was astounded by how brazen they were.

“They were very intimidating because they were dressed all in black and had black balaclavas underneath their helmets. All you could see was their eyes,” she said.