Veteran Trade Unionist Rab Knox, 61, who was dubbed Labour's "Mr Anti-Sleaze" in the late 90s, was working as a private-hire car driver when he attacked the 29-year-old. The former national union organiser pleaded guilty at Edinburgh Sheriff Court to carrying out the attack in the city’s Bingham area.

The court heard that Knox, of Blackchapel Close, Niddrie, had 'forcibly kissed' the woman, who was sitting in the front passenger seat of his private-hire car. He then forced her to perform a sex act in the vehicle - which was parked in Bingham Way - on December 3, 2002.

The 61-year-old rose to prominence after challenging the way public funds were wasted by regeneration groups in Craigmillar in the late 90s. He was known as Labour's 'sleaze-buster" for his outspoken criticism of those running the community organisations.

Knox - who also unsuccessfully stood as a candidate in the city's Alnwickhill ward during the 1992 local authority elections - was understood to have had close links with senior members of the Capital's ruling Labour administration before quitting the party.

Former Labour Party colleagues were today stunned to learn of the conviction. City council leader Donald Anderson said at the time "This is a shock. I don’t think anybody would have conceived that this could have happened."

A former full-time organiser for the Union of Shop, Distributive and Allied Workers, Knox previously served as chairman of Craigmillar Regeneration Action Group. He made headlines as a vocal critic of community groups in the area after their poor financial management was condemned in an independent report. He joined the Labour Party during the 60s and was became a well-known activist in the Edinburgh East and Musselburgh constituency.

Knox was convicted and jailed for 3 years in 2005 for his horrific sex attack on a woman passenger in his taxi cab.