Pc Stephen Dance said he was relieved the court case was over
A policeman has been found not guilty of assaulting a motorist he had stopped on suspicion of drink-driving.
Pc Stephen Dance, 44, of Cardiff, said it had been "sheer hell" since he was accused of punching Robert Davies in the back of a police car near Neath.
Mr Davies has since died in an unrelated car crash.
A Cardiff Crown Court jury took 80 minutes to clear Pc Dance, who denied causing actual bodily harm and perverting the course of justice.
Speaking after the verdict, he said: "The last 19 months have been sheer hell. I'm a professional police officer and I'm glad it's all over."
Pc Dance, who has been suspended from duty while the case was going on, said: "I can't wait to get back to the job I do so well."
Wayne Baker, secretary of the South Wales Police Federation, said: "He was acting in self-defence in a very difficult job, late at night, with someone who was drunk.
"We will be asking that he is reinstated as soon as possible."
The police officer denied repeatedly punching Mr Davies - although he told the jury he did hit him twice in self-defence.
Mr Davies was stopped while driving in Seven Sisters in October 2006.
Pc Dance and his colleague Pc Paul Jones gave Mr Davies a breath test which was positive.
He was told to get in the back of the police car while his girlfriend, Jade Davies, waited outside.
Other officers were called, and Mr Davies was taken to Neath police station, where he made a formal complaint against the officer.
Mr Davies was not charged with drink-driving as he was under the limit by the time he was tested again.
Pc Dance told the court he was pulled into the car by an "aggressive and abusive" Mr Davies, where a struggle ensued.
The court had heard from defence witness Pc Rebecca Thomas who had said Mr Davies was behaving "very aggressively" when she arrived on the scene.
She said her colleague, Pc Dance, had a swollen eye and she had noticed "reddening".