Chief Whip Andrew Mitchell resigns over 'Plebgate' After a month of intense political pressure Andrew Mitchell finally gave up the fight to keep his job tonight after admitting he could "no longer fulfil his duties" in the wake of his abuse of a Downing Street policeman. In a letter announcing his decision to resign, the former Chief Whip again denied that he had called the officer a "pleb" but admitted he had been unprofessional in his conduct. He also admitted for the first time that he had sworn at the officer concerned. "Whatever the rights and wrongs of the matter I will not be able to fulfil my duties as we would both wish," he said. Nor is it fair to continue to put my family and colleagues through this upsetting and damaging publicity.  He continued: "I did not, never have and never would call a police officer a "pleb" or a "moron" or used any of the other pejorative descriptions attributed to me. "The offending comment and the reason for my apology was my parting remark "I thought you guys were supposed to f***ing help us." It was obviously wrong of me to use such bad language and I am very sorry about it. Click here to read the resignation letter in full Mr Cameron has now been forced into an unwelcome reshuffle to replace Mr Mitchell just a month after promoting him in the reshuffle from his previous job as International Development Secretary. Last night it was announced that his position would be taken by Sir George Young, 71, who was dropped as Leader of the House of Commons in the reshuffle. Mr Mitchell is expected to make a resignation statement to the House of Commons next week. Downing Street sources said that Mr Cameron met Mr Mitchell at 4pm this afternoon after the Prime Minister returned from the European summit in Brussels. Mr Mitchell made the decision to go on Thursday night and contacted Downing Street this morning asking for a private meeting with Mr Cameron "at the earliest opportunity." It was arranged that he would drive down to the Prime Minister's country residence at Chequers this afternoon where he told him of his decision to step down. "This has all happened very quickly," said a Downing Street source. We didn't know anything about it until this morning. Mr Mitchell is understood to have concluded that his position was untenable following a meeting of Tory backbencher 1992 Committee on Wednesday night. Four MPs openly demanded that he step down at while others expressed concern at the damage the affair was doing to the image of the party following a concerted campaign by the Police Federation. Mr Mitchell felt in particular that he had lost the confidence of the 2010 intake of MPs, and was also facing a Labour motion next week to dock his pay. The deputy chief whip John Randall had also reportedly been talked out of quitting in protest at his boss's determination to stay in his job. Sources close to Mr Mitchell said he had taken "extensive soundings" from backbench MPs and felt in particular that he had lost the confidence of the 2010 intake of Conservatives - who make up half the Parliamentary party. The former Conservative whip Michael Fabricant said he had urged Mr Mitchel to step down. "I spoke to Andrew yesterday about this and I was frank," he said. This has been playing out like a long Greek tragedy and I hope that now he will take a break and rebuild his strength. He is a very able individual and I am sure he will return to public life in due course. Another Tory MP last night said: "It was the right thing to do." His opposite number in the Liberal Democrats Alan Carmichael added that the scandal had "clearly taken a heavy toll on him personally." In his letter accepting Mr Mitchell's resignation Mr Cameron help open the possibility that he might be able to return. "I regret that this has become necessary," he said. As you have acknowledged, the incident in Downing Street was not acceptable and you were right to apologise for it. You have much to be proud of from your service on the Frontbench both in Opposition and in Government, and your continued service to your constituents in Sutton Coldfield. I hope that, in time, you will be able to make a further contribution to public life. Paul McKeever, chairman of the Police Federation of England and Wales said: "It is not good to see anyone fall from public office but the decision by the Prime Minister to accept Andrew Mitchell's resignation seemed almost inevitable. Andrew Mitchell has apologised to our Metropolitan Police colleague and our colleague has accepted the apology. We hope this matter is now closed. Yvette Cooper MP, Labour's Shadow Home Secretary, said: "This is a sensible decision by Andrew Mitchell. It is very unfortunate that David Cameron allowed this to drag on so long rather than investigate and resolve it at the start. Letting it carry on like this sent a very bad signal to the police and public servants across the country about the Government's attitude.