A manhunt has been launched after a gunman threatened a policeman outside a school.

Schools in Didcot were locked down at about 2pm today after the gunman confronted an officer in Kynaston Road. The man hid in a cemetery behind St Birinus School, Mereland Road and the area was closed down.

Police spent an hour searching the cemetery with a police helicopter and dogs, but gunman has not been found.

Officers are now carrying out search of the wider Didcot area. Chief Supt Paul Sullivan, who is leading the operation, said: "Nobody has been shot or harmed in this incident and we are now carrying out a number of enquiries in an effort to find this man.

"I wish to advise members of the public that if they see this person, do not approach him, but contact the police and we will respond immediately."

No shots were fired and no one has been injured.

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

Police spokesman Toby Shergold said a police patrol car followed a black VW Golf seen being driven erratically from Oxford's eastern bypass at 12.55pm.

The driver jumped out of the car in Kynaston Road and pointed a gun at a police officer. He then disappeared into Didcot Cemetery and has not been spotted since.

At about 2pm local schools including St Birinus School and Willowcroft Community School were told by police to close and lock the doors because a dangerous man was in the area.

Chris Bryan, headteacher at St Birinus School, said: "We had a call from Thames Valley Police saying a dangerous person was in the area and to keep everybody inside.

"We carried out our emergency procedure and kept everyone inside until the police gave us the all clear. We were told to keep everybody inside the building and safe. The children and parents were very understanding because their personal safety comes first."

Police gave the all-clear to both schools at about 2.45pm.

Children have now been allowed to go home but younger ones are being collected by their parents. Anyone with information on the gunman should contact police on 08458 505505 or Crimestoppers on 0800 555111.