A gunman was on the loose tonight after threatening a police officer in Didcot.

Two schools were 'locked down' after the man brandished the weapon when he was stopped by police in Kynaston Road this afternoon.

The man then fled towards a cemetery which backs on to both St Birinus School and Willowcroft Community School, in Mereland Road.

Hundreds of pupils were ordered inside, and doors and windows were locked while armed police combed the area.

Despite an hour-long search, involving sniffer dogs and a helicopter, neither the gunman nor the gun was found. Officers last night extended the search across the town.

The incident began when police spotted a black Volkswagen Golf driving erratically on Oxford's Eastern Bypass and followed it to Didcot.

Dan Corker, 13, a pupil at St Birinus School, said: "We should have been going home, but were told to stay in our classrooms. It was then that we knew something was wrong.

"The doors and gates at the school were closed. We were told later that a gunman had been in the area. That was scary, particularly when you know of shootings at schools in the US."

The 270 pupils at nearby Willowcroft Community School gathered in the main hall for their own safety. Police gave the all-clear at 2.45pm.

At the school gates Shirley Murrell, who had arrived to pick up her eight-year-old son Ashley, said: "It was very frightening. I'm thankful that everyone is safe."

The school's headteacher, John Gray, said: "It was nerve-racking, because we did not know what was happening."

Chris Bryan, headteacher at St Birinus School, said: "We carried out our emergency procedure and kept everyone inside until the police gave us the all-clear."

The gunman is described as black, 5ft 9in, in his late teens or early 20s, with a short Afro-style haircut. He was wearing jeans, trainers and a black Puffa jacket.

Anyone with information should call police on 08458 505505 or Crimestoppers on 0800 555111.