David Cameron: no need to investigate Andrew Mitchell's four-letter police rant The Prime Minister has heard Mr Mitchell's version of the tirade but has not spoken to any senior police officers or requested a police log of the incident. A Number 10 spokesman said this would not be appropriate as no formal complaint has been made. He would not say whether CCTV footage of the incident has been reviewed. This morning, Mr Mitchell publicly said sorry for not giving the police officers "the respect they deserve" in his first televised appearance since the incident last week. He admitting losing his temper after a "long and extremely frustrating day" and said he did not use the words attributed to him. However, he declined to explain exactly what happened during the row about whether he could cycle his bike through the main gates of Downing Street. Number 10 had been hoping Mr Mitchell's appearance in person would "draw a line" under the incident but this morning the furore showed signs of escalating. Nick Clegg, the deputy Prime Minister, waded into the debate by saying Mr Mitchell should give a full explanation. "I think, therefore, it's really important that Andrew Mitchell explains fully and in detail his version of events," he told the BBC. A Number 10 spokesman said Mr Clegg accepted the minister's apology was the "key thing." Two other senior Liberal Democrats added further fuel to the fire. Jeremy Browne, a minister in the Home Office, said there are more "loose ends" that need explaining and Sir Menzies Campbell, the party's former leader, said the story "still has legs." In a further blow to Mr Mitchell, the Metropolitan Police Federation and the Police Superintendents' Association are refusing to accept the second apology. John Tully, chairman of the Metropolitan Police Federation, today demanded a "full and frank inquiry" to establish who is telling the truth. Chief Superintendent Irene Curtis, president-elect of the Police Superintendents' Association, also said it was still uncertain whether Mr Mitchell used the word "pleb." She said: "We are five days on from when this incident happened and we're still no clearer as to what was said. By saying he disputes what the officer has said, he's actually calling into question the police officer's integrity, and for a police officer that's a very serious matter. The Metropolitan Police is now investigating how the verbatim reports of police officers have made their way into the hands of The Sun.