LONDON, England (AFP) — British cabinet minister Andrew Mitchell resigned yesterday after launching a foul-mouthed tirade at police officers guarding the gates of Prime Minister David Cameron's Downing Street office.

Mitchell, who as the government's chief whip was supposed to enforce discipline in Cameron's Conservative party, handed in his resignation after nearly one month of intense pressure over his behaviour.

He denied accusations that he had called police "plebs", but admitted using bad language to the officers after they stopped him going through the main gate on his bicycle, directing him to a side gate instead.

The row was damaging for the Conservatives as they face growing accusations that the privileged backgrounds of Cameron and other senior party members, including Mitchell, are out of touch with voters.

The new chief whip will be George Young, the former leader of the House of Commons. British media pointed out that Young is like Mitchell, a keen cyclist and went to the elite Eton College, where Cameron was educated.

In his resignation letter, Mitchell, said: "The offending comment and the reason for my apology to the police was my parting remark 'I thought you guys were supposed to (expletive) help us'."

Part of the offensive word was replaced by asterisks in the copy of his letter officially released by Downing Street.

Citing the "upsetting and damaging publicity", Mitchell said that "whatever the rights and wrongs of the matter I will not be able to fulfil my duties as we would both wish".

He added: "I have made clear to you — and I give you my categorical assurance again — that I did not, never have and never would call a police officer a 'pleb' or a 'moron' or use any of the other pejorative descriptions attributed to me.

"It was obviously wrong of me to use such bad language and I am very sorry about it and grateful to the police officer for accepting my apology."

Police representatives had called for Mitchell's resignation, saying his outburst was particularly badly timed because it came in the week that two policewomen were shot dead in the city of Manchester in north-west England.

Cameron wrote back that he was sorry to receive Mitchell's resignation but understood why he had decided to quit.

"I regret that this has become necessary," the prime minister wrote.

"As you have acknowledged, the incident in Downing Street was not acceptable and you were right to apologise for it."