Kerry Smith has quit as Ukip's candidate in a top target seat after being forced to apologise for a series of offensive comments.

In recordings of phone calls obtained by the Mail on Sunday, the would-be MP was said to have mocked gay party members as "poofters", joked about shooting people from Chigwell in a "peasant hunt" and referred to someone as a "Chinky bird".

They were revealed just days after he was reinstated as the party's general election candidate in South Basildon and East Thurrock.

He initially apologised and explained that he had been under great stress at the time of the comments and taking strong pain killers.

But in a statement, he said: "I have this evening offered my resignation as Ukip PPC for South Basildon and East Thurrock.

"I want the best for South Basildon and East Thurrock and I want to see the real issues discussed that touch the lives of people.

"Therefore I have chosen to resign so that Ukip can win this seat next May."

Mr Smith was deselected as the candidate for South Basildon and East Thurrock in October - with Neil Hamilton, the former Tory minister who is now Ukip's deputy chairman, the most prominent of those in the frame to take the nomination.

But Mr Hamilton ended up endorsing the Essex county councillor in his hustings speech after Mr Smith was reinstated - leading the ex-Conservative to lash out at party insiders over a "dirty tricks" campaign being run against him.

His tirade against the "cancer at the heart of Ukip" came after a letter from the party's finance committee about his expenses claims was leaked.

Mr Hamilton called for the party's national executive committee (NEC) to take action against those involved in the "black arts of selective briefing, misrepresentation and outright lies".

Ukip MEP Patrick O'Flynn, who is the party's candidate in the running to become Cambridge MP, confirmed Mr Smith had not been fired as a result of the scandal.

He pointed out the recorded phone call was some time ago when Mr Smith was on prescription sedatives after an injury and not thinking rationally.

Mr O'Flynn told the BBC's Sunday Politics: "I'm on the Douglas Carswell side of this where he says what many people call political correctness is often just politeness.

"Using derogatory, pejorative slang is not right at this level of politics and you shouldn't do it."

Asked why Mr Smith was previously dropped as a candidate, Mr O'Flynn said he was not sure.

But he insisted: "If Kerry Smith was seriously homophobic, then he clearly would not have been backing David Coburn (MEP for Scotland) who is gay over Stephen Woolfe (Ukip immigration spokesman) who is not.

"He needs to learn to express himself more respectfully about minorities of all kinds now he is off the prescription drugs and he is our candidate.

"He is very popular... He is a young man, he is learning politics.

"We don't want to become so anodyne and speaking in such non-colloquial language that we lose touch and I think some of the other parties risk doing that.

"But clearly what he said there is unacceptable. He has apologised unreservedly. There are big mitigating circumstances. It is from some time ago and we are willing now to judge him on his performance going froward from now."

On the party's wider prospects, Mr O'Flynn accepted the "hand grenades are rolling down the corridor again".

But he added: "We are still way up in the polls. We have had a fantastic year. We have won a set of nationwide elections. We have won two by-elections against expectations of Tory high command."

He also pointed out there were rows over inappropriate comments in relation to both Labour and the Conservatives as well last week, namely Aberdeen North MP Frank Doran's claim the post of fisheries minister was not suitable for a woman and Tory peer Baroness Jenkin's remark that the poor "don't know how to cook".

In the leaked recordings, Mr Smith is said to have claimed Mr Farage was bribed into promoting Mr Woolfe over Mr Coburn when they were candidates in the 2012 London Assembly elections..

But he later allegedly confirmed there was no evidence to substantiate the claim, adding: "If we had proof Nigel would be gone."

He is also understood to have attacked Olly Neville, former leader of Ukip's youth wing who was sacked last year after saying he backed gay marriage.

According to the Mail on Sunday transcripts, Mr Smith said: "Olly Neville - the sun shines out of his rear end. He is now setting up BLT Ukip on Facebook. What the old poofter groups call themselves.

"I just call it BLT like the sandwiches. It's them letters BLT with a Q on the end, bacon lettuce and tomato.

"It's got our logo done with a rainbow. F*****g loopy. That's been approved by the NEC. That's f*****g disgusting."

Mr Smith is also said to have mocked Lucy Bostick, a Ukip activist in Chigwell, for printing "boring c**p" on her leaflets.

According to the transcripts, he said: "This is Chigwell. If she was doing a survey in Chigwell the question should be 'Do you oppose the EU banning the use of lead in shotguns as that way you can shoot more peasants coming from Chigwell? 'Do you support a peasant's hunt through Chigwell village?'"

In addition he is understood to have referred to a "Chinky bird" he claimed gatecrashed a Ukip rally and lunch with Mr Farage.