David Cameron was last night accused of leaving Andrew Mitchell “swinging in the wind” because he knew about evidence that undermined policemen's allegations against him – and could have saved his political career.
Friends of the former Chief Whip said it was "disgraceful" that Mr Cameron had not called for an official investigation once Downing Street CCTV footage had directly contradicted the officers' accounts of the incident. Instead, they suggested, Mr Cameron had made a calculation that the only way to save Mr Mitchell's career would have been to accuse the policemen – who are responsible for protecting senior politicians – of lying, which he was not prepared to do.
The Independent revealed yesterday that the Prime Minister had known for almost three months that at least one member of his elite protection unit may have fabricated parts of the Downing Street police log about the confrontation with Mr Mitchell.
The Independent understands that Mr Mitchell himself did not see the CCTV footage before he resigned, instead being told by officials that the tape was "of low resolution and you couldn't lip-read" what was being said.
He was not told by either Mr Cameron or Downing Street officials that the footage contradicted police statements about the affair.
The policemen claimed that members of the public looked on at the incident and were "visibly shocked" at the language used.
The CCTV footage also contradicted the critical email – supposedly sent by a member of the public – that appeared to back up the police version of events.
It was only after Mr Mitchell resigned that his wife Sharon and his political friends encouraged him to fight back and demand to examine the CCTV images himself, which contradicted the policemen's account.
Last night Mr Mitchell's friends expressed anger that Mr Cameron and the Cabinet Secretary Sir Jeremy Heywood had failed to act on the evidence earlier. "This was not a minor error in the log," one friend said. "If this had gone to court, a defence barrister would have destroyed the police officer for the inconsistencies.
"I am amazed that no one had a conversation with Bernard Hogan-Howe three months ago [when Mr Cameron knew]. It was a disgraceful decision to let it lie and let Andrew swing in the wind."
Labour sources also expressed concern over the apparent inaction. One Labour figure said: "It is frankly incredible that on the face of it you had a policeman on the gates of Downing Street whose statement appeared materially false and you don't order an investigation to look into it. What planet were they on?"
They also questioned why, when the Shadow Home Secretary Yvette Cooper had written to Sir Jeremy calling for an investigation and an examination of the CCTV footage, she was stonewalled. "We now know that there was an investigation of sorts but it was decided not to do anything about it," they said. "It is important to know why."
Speaking on a visit to Afghanistan Mr Cameron said he took "full responsibility" for the Downing Street investigation. He also revealed that he had met Mr Mitchell the night before a Channel 4 news and Dispatches investigation broadcast the CCTV evidence which suggested the police account of the altercation was flawed. "I saw him in No 10. I spoke to him and my office has been in contact with him, as you would expect, fairly regularly," he said.
Asked what frame of mind Mr Mitchell was in, Mr Cameron replied: "I thought his mood was very calm and rational given what were very disturbing revelations."
Mr Cameron did not rule out a return to government by Mr Mitchell in the future. However he cautioned: "One step at a time. Let's get to the truth about what happened.
"But I think it has been an extraordinary development, frankly, to find a police officer apparently posing as a member of the public, pretending to have been outside Downing Street at the time and then trying to blacken the name of a minister."
Downing Street also expressed confidence in the current police investigation into the affair, under Mr Hogan-Howe.
"The Prime Minister has full confidence in the Metropolitan Police Commissioner and believes the police should be allowed to carry out the investigation, which is being overseen by the Independent Police Complaints Commission," said an official spokesman.
A spokesman for the Mayor of London Boris Johnson also expressed solidarity. "The Mayor has absolute confidence in the Commissioner.
"He has assured the Mayor that he is determined to get to the bottom of this as quickly as possible.
"The Mayor has every confidence in that assurance."