AN off-duty police officer was gunned down and killed in the street after he rushed out of his house to tackle a gunman.

PC Ian Dibell, 41, was shot dead outside his home in Clacton-on-sea, Essex, when he went to help a couple who were being chased by the shooter just before 3.40pm yesterday.

Last night, as a manhunt got underway, Essex police chief Jim Barker-McCardle vowed not to rest until the killer was found, adding: "Policing is a family and we are all hurting."

Officers are searching for Peter Reeve, 64, in connection with the incident, which also left another man injured.

Residents were warned to stay indoors and avoid approaching Reeve, who was described as dangerous, as armed officers spread throughout the town.

PC Dibell, who has been with the Essex force for 10 years, was praised for his bravery as Mr Barker-McCardle told how he "deliberately intervened in what he knew was an extremely deadly situation". The police chief said PC Dibell was "an experienced and professional neighbourhood police officer".

He added: "Our thoughts and prayers are with the family of our brave, fallen colleague."

PC Dibell was divorced and lived with his girlfriend Louise Lilley, a police community support officer,

One local resident told how the gunman shot the man he was chasing before turning the gun on the policeman. The resident said: "He fired about three shots and one caught the man and he went down. Next thing I knew another shot was fired and the policeman was on the floor. I think he was shot in the head."

Neighbours added that Reeve was a loner who had been locked in a long-running feud with the couple over noise and parking.

Paul McKeever, chairman of the Police Federation of England and Wales, said PC Dibell had shown "remarkable courage".

Mark Smith, chairman of the Essex Police Federation, added: "Constable Dibell was a dedicated professional who, even though off duty, has paid the ultimate sacrifice for his bravery and selfless actions in trying to protect his local community."

More than 100 police officers from Essex and neighbouring forces joined in the hunt.

The man who was injured by the gunman suffered leg injuries and remains in hospital. It is understood he knew Reeve and gave his name to police.