Gurpal Virdi, 56, was yesterday cleared of the charges at Southwark Crown Court in London in the incident alleged to have happened in 1986.
"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," he told the court.
In 1998, Virdi gave evidence to the Stephen Lawrence inquiry into racism in Britain's largest police force.
In reference to the assault allegations, he said: "It was done to keep me quiet and then to make me look bad in the community, and people did avoid me. It was meant to destroy me."
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Virdi has won two employment tribunal cases against the Metropolitan Police - one after he claimed to have been framed by colleagues, and the other after claiming to have been victimised.
After the verdict, Virdi's solicitor, Matt Foot, called for an inquiry into why the case had been brought despite lack of strong evidence: "It's absolutely disgraceful that he has had to go through this. I believe if it had been somebody else, other than Gurpal Virdi, they would not have been prosecuted.
"He feels he has been further hounded by the Met because he stood up to racism in the police force."
"That investigation was entirely focused on securing what evidence was available, with respect to what were undeniably very serious allegations. It would not have been proper to proceed in any other way.
"We presented the evidence to the CPS [Crown Prosecution Service] who decided the allegations and evidence should be heard by a jury.