Mr Whitty was arrested for assaulting a police officer only after passing a breath test at a police station where he had been taken on suspicion of drink-driving, Bow Street magistrates' court in central London was told.
After the case Mr Whitty said: 'I am delighted with the result. I have always asserted my innocence and now I am glad that my name has been cleared.'
However, he was fined pounds 50 and had his licence endorsed after being found guilty of jumping a red light during the incident.
The prosecution alleged that Mr Whitty, 49, of Peckham, south London, had tried to escape because he feared he was over the drink-drive limit after a party following Labour's election defeat.
A uniformed police officer suspected him of drink-driving and asked him to get out of the car. Mr Whitty was alleged to have said: 'Leave it out, I have had a fucking bad enough night already.' He then sped off through a red light pursued by a police van and officers from an Armed Response Unit passing on routine patrol.
Jeffrey McCann, for the prosecution, said Mr Whitty was stopped only after the armed response car blocked a road following a high-speed car chase. Police claimed he was abusive and struggled violently when they tried to arrest him. While trying to handcuff him he threw his arms about and kicked out with his feet, injuring one officer.
Mr Whitty denied assault. He said he was driving to meet Neil Kinnock at Labour Party headquarters with Eileen Ryan, his assistant, and Mary Docherty, a party fundraiser. He said his driving was normal and denied swerving across the road.
While stopped at a red light a police officer banged on his boot and 'aggressively' asked him to get out of the car. After an exchange he said he made the mistake of driving off at speed.
Geoffrey Robertson, QC, for the defence, said there were 'manifest discrepancies' in the police versions of the story.