Mitchell comments 'beyond unacceptable', says top Lib Dem Police suggested the Tory enforcer was close to being arrested after allegedly shouting "learn your f****** place" when he was stopped from cycling out of Downing Street's main gates. Liberal Democrat president Tim Farron said the comments, as reported, were "beyond unacceptable." "If he said what it is reported he said, it is absolutely appalling," he told the BBC. All of us can have grouchy moments and say things we regret but it reveals, what he is reported to have said, something not terribly pleasant. Having said that, a lot of this stuff is still yet to be revealed. It is David Cameron's job to discipline his minister in the same way that if it was the Liberal Democrat chief whip, who I am sure would never do a thing like this, it would be Nick Clegg's job. But certainly the comments reported are utterly, indeed beyond, unacceptable. Although Mr Mitchell, the former shadow police minister, has apologised for not treating officers with due respect he has denied using some of the language reported. Labour said Mr Mitchell was either accusing the member of Scotland Yard's Diplomatic Protection Group, SO6, of lying or he must have used the foul language, potentially an arrestable offence. John Tully, chairman of the Metropolitan Police Federation, said Mr Mitchell was warned to curb his behaviour by officers at the time of the rant and was likely to have been arrested if he had continued. "There is a written record of the incident in the officers' notebooks," he told Channel 4 News. I understand that following his tirade to the officers he was warned and he desisted. I think had he continued he would have been arrested. He added: "He should resign. As a Cabinet Minister it's unacceptable for someone of his standing to use such disrespectful and abusive language to a police constable let alone anyone else. David Cameron dodged questions about whether he planned to sack Mr Mitchell and condemned his behaviour as "wrong" and "inappropriate." What Andrew Mitchell said and what he did was not appropriate. It was wrong and it is right that he has apologised," he said. Mayor of London Boris Johnson was said to be "deeply unimpressed" with Mr Mitchell's behaviour while former Conservative Party chairman Lord Tebbit denounced the comments as "extraordinarily stupid" and urged Mr Cameron to have a "heart-to-heart talk" with his new chief whip. Mr Mitchell, who was also a minister under John Major in the early 1990s, apologised in a statement. The MP for Sutton Coldfield said: "On Wednesday night I attempted to leave Downing Street via the main gate, something I have been allowed to do many times before. Senior Tory backbencher David Ruffley defended his colleague. "I have known Andrew Mitchell since he became shadow police minister, a post I subsequently held," he said. So I can attest to the fact that he has the highest regard for the police service of this country. As a strong supporter of tough, traditional law and order policies, Andrew understands the central importance of police officers in fighting crime and keeping us safe. Nothing that may have occurred this week should affect his well-deserved reputation for being on the side of policemen and policewomen. Earlier this year Scotland Yard Commissioner Bernard Hogan-Howe said there "were still opportunities" to arrest members of the public for swearing at police despite a judge ruling that it is not a crime. Asked if Mr Johnson stood by comments he made last year that people who swear at police should expect to be arrested, the Mayor's official spokesman said: "Yes, he does." Asked if the chief whip should remain in post, he added: "That is not a matter for the Mayor, it is a matter for the Prime Minister and Mr Mitchell." Ken Clarke, minister without portfolio, said: "I have known Andrew for a long time and he is a perfectly reasonable, courteous man with the same high regard for the police services as anyone else. He obviously had a flare of bad temper on this occasion and has rightly apologised. I do think this should be allowed to set the matter at rest.