A police officer has been cleared of assaulting a pro-hunt demonstrator during protests outside the Houses of Parliament.

Pc Neil Latteman, 43, was cleared a year to the day since the violent clashes in Parliament Square in Westminster when protesters threatened to break police lines and storm the building.

Latteman, who has been in the police for 22 years and is part of the Met's Territorial Support Unit, insisted he punched North Yorkshire farmer Mark Faulkner, 34, once in the face to subdue him in line with approved police tactics.

Mr Faulkner, an arable and game farmer who lives near Thirsk, had been trying to incite the crowd in Parliament Square to break police lines, the defence claimed.

District Judge Timothy Workman, sitting at London's Bow Street Magistrates' Court, said: ''He clearly maintained he was acting to assist the arrest and used an approved technique which he insisted were necessary in the circumstances.

''I cannot be sure that the defendant was lying when giving his evidence that he was acting lawfully in striking Mr Faulkner, therefore the case is dismissed.''

Mr Workman said the issue was whether the blows struck against Mr Faulkner were, as argued by the defence, lawful because they had been delivered in self-defence.

The court was told that within the past year Latteman had been taught a technique to stun struggling suspects with a hard blow to a cluster of nerves in the neck and face. In his notes, produced hours after the incident, Pc Latteman wrote: ''I threw one punch in his face, fearing for my safety.''

But witnesses alleged he threw at least two ''unprovoked and unnecessary punches'' and acted ''like a football hooligan''.

Latteman claimed he believed Mr Faulkner was a threat to himself and his fellow officers, adding that he was ''snarling'', kicking out with his feet and out of control.

Scaffolding clips, fireworks and bottles, some of them filled with urine, were being hurled at the lines of officers by the crowd at the time of the incident. Mr Faulkner was already under arrest and surrounded by eight or nine officers.

The incident was filmed by Stephen Jackson, a resources technician and private investigator, and the tape was studied by the Independent Police Complaints Commission.

Mr Faulkner was at the front of the protest when he was hit twice by a police officer with a baton, causing him to fall and lose consciousness. He was then pulled from the crowd for an alleged breach of the peace and pushed against a police van where the incident with Latteman happened. Mr Faulkner suffered a bruise to the front of his head, a black left eye, an injured lip and bruising to his elbow, but it is impossible to say in which incident these injuries were caused.