A retired Asian detective has been found not guilty of sexually assaulting a teenage boy in the back of a police van nearly 30 years ago.

Gurpal Virdi, 56, was accused of handcuffing the 16-year-old, called him a "n*****" and then prodding him in the bottom with a truncheon during the incident on November 7 1986.

But he was acquitted by a jury after just one hour of deliberation, an official at London's Southwark Crown Court said.

During the trial Mr Virdi accused the Metropolitan Police of bringing the criminal case against him as part of a 17-year campaign to "hound" him out of the force.

The retired detective told the court: "I totally deny the allegations".

He accused the police of trying to discredit him after he gave evidence to the Stephen Lawrence inquiry about racism within the police force.

He told jurors: "This is a typical reaction from a department that has hounded me since 1998, investigating me and following me around and bugging my phone. Doing all sorts of things."

Mr Virdi, a married father-of-two from Hounslow in west London, was found not guilty of indecent assault on a male and misconduct in public office.

The alleged attack was said to have happened when Mr Virdi was attached to the crime squad in Battersea, south London.