An armed raid on a security van in Cambridge is being linked to two earlier robberies.

Cambridgeshire Police believe the same man committed three robberies in and around Cambridge and Sawston, targeting off-licences and security vans. The latest was at 1605 GMT on Tuesday in Norwich Street in Cambridge. A man armed with a gun approached a security van outside the HSBC bank and took a substantial amount of cash from the guard. The first robbery was on Sunday at 1955 GMT when a man entered Threshers on Mill Road in Cambridge. He pulled out what has been described as a shotgun and demanded money. The second raid was at the Unwins off licence in Sawston on Monday at 2020 GMT. Police are looking for a white man, in his late 30s, 5 ft 6 ins tall, stocky, with short brown hair. He was wearing dark clothes and a light coloured baseball cap.