Government Chief Whip Andrew Mitchell submits to police pressure and resigns, after admitting he swore during a confrontation with police officers at Downing Street.
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The resignation comes after a row involving Mr Mitchell swearing at police dragged on for weeks, with the beleagured MP failing to draw a line under the scandal that emerged after he allegedly swore at police.
In his resignation letter Mr Mitchell again claimed he had not called a police officer a "pleb" or "moron" or "any of the other pejorative descriptions attributed to me".
He went on to admit it was wrong to use bad language to the police and thank the prime minister for the opportunities provided to him. Mr Mitchell claimed he said "I thought you guys were supposed to f****** help us".
Prime Minister Cameron wrote in a letter accepting the resignation "I understand why you have reached the conclusion you have."
"As you have acknowledged, the incident in Downing Street was not acceptable and you were right to apologise for it."
Sir George Young will now take over as chief whip, Downing Street has confirmed.
The Police Federation and Labour were among those calling for the minister to go as pressure intensified on him. There were also heated clashes in parliament on Wednesday.
Police Federation chairman Paul McKeever 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."
The incident in September allegedly saw Mr Mitchell swear at police officers stationed at Downing Street, after they stopped him leaving through the main entrance gate with his bicycle.
Paul McKeever, chairman of the Police Federation of England and Wales, said Mr Mitchell's resignation "seemed almost inevitable".
Labour said Mr Mitchell should have gone earlier and questioned the Prime Minister's judgment in allowing him to remain place.
Shadow Cabinet Office minister Michael Dugher said: "What people will want to know is why, when the entire country could see that what Andrew Mitchell did was wrong, the Prime Minister totally failed to act.
"David Cameron is left looking profoundly weak and totally out of touch, doing everything he could to hold on to Andrew Mitchell only for his chief whip to bow to the inevitable, given the understandable public anger."
Shadow Home Secretary Yvette Cooper 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."