Former British minister Andrew Mitchell is suing Rupert Murdoch's The Sun newspaper over a report which claimed he called police officers "plebs" and which cost him his job, his lawyer said.
Mitchell was forced to quit a senior position in Prime Minister David Cameron's Conservative party in October after police claimed he verbally abused an officer.
The policemen had stopped him from cycling out of the main gates of Downing Street, where Cameron's office is located, in September.
Mitchell admitted there was an ill-tempered exchange but always denied he used the derogatory word "pleb", as reported on the front page of the best-selling tabloid.
He subsequently complained to the police that the officers had lied, and so far four people have been arrested as part of a wider probe into the incident, including three serving officers.
Two policmen on duty in Downing Street that day are accused of leaking information to the media, while the third officer who was not working there at the time is suspected of misconduct.
A friend of Mitchell's told the BBC he was suing The Sun to address a "campaign of vilification" against him.
"It's always risky suing papers but he thought he had no alternative," the friend said Thursday.
Mitchell's lawyer Graham Atkins confirmed that he had launched legal proceedings for libel against the owners of The Sun.
"There are a number of other potential actions being considered but I do not intend commenting any further at this stage."
A Sun spokesman responded: "We stand by our story and will defend this claim vigorously."
Mitchell had been international development minister in Cameron's cabinet before being moved to chief whip, a job enforcing discipline in the parliamentary party which he quit in October.