Sir John Randall, Uxbridge and South Ruislip Conservative MP, pictured, was the man first contacted by PC Keith Wallis, a constituent, through the email that purported to be from an eye-witness to the fracas between Andrew Mitchell and the Downing Street officers.

Mr Randall, at the time the Government's deputy chief whip, was subsequently asked to go round to Wallis's house in Ruislip to try to get to the bottom of the matter.

Channel Four's Dispatches programme got wind of the affair shortly after and things unravelled rapidly.

In a statement to the Gazette last night, Mr Randall said: "Although there are still two outstanding libel actions I am personally very pleased that this affair has been concluded.

"I like others have found the past year to be one of the most difficult periods that I have had since entering Parliament.

"The Independent Police Complaints Commission says the evidence from emails, text messages and telephone calls did not suggest an organised conspiracy to bring down a cabinet minister. "However, it does say 'there was clearly collusion between certain officers to, as they saw it, blow the whistle on bad behaviour toward one of their own, which ultimately had the same effect.'

"Strangely the argument has raged over what were the actual words used, and again the IPCC says: 'I do not think it is possible to establish exactly what was said during the initial altercation.'

"The Director of Public Prosecutions herself stated that during the investigation they looked at previously unseen, unedited CCTV footage from Downing Street, not referred to by the media.

PC Wallis has been severely punished for 'lying and for devious misconduct which fell far below the standards expected of a police officer'.

"We will never know what drove him to do such a thing. I am sure that his fellow officers are as disappointed as I am that his actions have had such repercussions for the reputation of the police service as well as causing distress to individuals.

"I remain clear that the actions of one individual should not be used to attack the reputation of our excellent police force."