Police suspicion fell on Mr Virdi, of Cranford near Heathrow, who, it was suggested, was plotting to lodge a claim of racial discrimination because he had been turned down for a promotion.

Virdi case timeline

Dec 97-Jan 98: Racist letters sent to non-white officers April 98: Mr Virdi arrested Feb 2000: Appears before police tribunal March 2000: Found guilty and dismissed Aug 2000: Employment tribunal finds him victim of racism Nov 2000: Offered reinstatement and apology Feb 2001: Receives a reported �200,000 settlement

A specialist police team searched his home for over seven hours in April 1998, and he was arrested for offences of distributing racist hate mail and suspended from his post.

He was accused of creating the letters on his own computer at work just hours before they were delivered.

Investigating officers, who described Mr Virdi's actions as "despicable", also accused him of trying to frame a female colleague by sending some letters using her secret password.

The Crown Prosecution Service decided not to proceed with criminal charges, but in February 2000 Mr Virdi appeared before a police disciplinary tribunal.

A month later he was found guilty and dismissed from the force.

The Sikh officer, who himself had given evidence on racism in the Met Police to the Stephen Lawrence inquiry, took the force to an employment tribunal.

Substantial compensation

Mr Virdi was successful in his attempt, and in August 2000, the tribunal found that he had been discriminated against on the grounds of his race.

The tribunal said that during the investigation into the race letters, Mr Virdi was treated differently to a white female officer, Pc Jackie Bachelor, who was also a suspect.

While Mr Virdi's home was searched, Ms Bachelor's was not.

Met Police actions

Accused Mr Virdi of plotting letter campaign Seven-hour search of his home Accused of framing female officer Tried to entrap him in taped interview Branded his actions "despicable"

Ms Bachelor was also said to have been interviewed in an informal way, while the tribunal said the Met Police has tried to "entrap" Mr Virdi in a taped personnel interview.

It concluded the Metropolitan Police could not claim it had carried out good investigation practice.

"We therefore find that Gurpal Virdi has been the subject of discrimination on the ground of his race," it ruled.

Speaking after the ruling, Mr Virdi said: I wanted to be a policeman and I maintain that the police service is a good service."

The father-of-two was awarded �150,000 in compensation following the hearing, while Scotland Yard later agreed a settlement of a reported �200,000 to compensate him for his loss of career and injury to his feelings.

In November 2000, Mr Virdi was offered reinstatement to the force but, because of legal issues relating to the employment tribunal, he has yet to return to work.