An hour-long siege at a supermarket ended peacefully after a knifeman surrendered his weapon.

Police, some wearing stab-proof vests, helmets and carrying shields, surrounded the Somerfield store in High Street, Witney, after receiving reports yesterday that a man carrying a large knife had shut himself in an office.

Police evacuated the store and called in negotiators.

The man, who was alone, was eventually persuaded to throw his knife out of the window. Thames Valley Police area commander Supt John Reeve said: "The policy was to work towards an outcome where nobody got injured, either the man in the office, police officers, members of staff or the public.

"We cleared the area around the office and ensured that nobody could get in or out. We called in negotiators to talk to the man and contacted members of his family to inform them what was happening. "I am pleased to say that after an hour he was persuaded to drop the knife out of the window. We entered the office and took him into protective custody."

Supt Reeve said there was nothing at this stage to indicate what sparked off the incident.

A 38-year-old man was today being held at Witney police station.