Farage's political career on line as Ukip revolts over leadership
Nigel Farage's leadership of Ukip is under intense pressure after a major donor backed demands for him to quit.
Spread-betting tycoon Stuart Wheeler's call for Mr Farage to stand down came after the party's election campaign director Patrick O'Flynn claimed the leader was turning the party into a "personality cult".
Ukip MEP Mr O'Flynn denied he was launching a "coup" against Mr Farage but hit out at "poisonous individuals" in the leader's inner circle who he claimed wanted to push the party into a "hard-right, ultra-aggressive American Tea Party" approach.
Party secretary Matthew Richardson, one of the aides reported to be the target of Mr O'Flynn's attack - although not named by the MEP - has offered his resignation, according to Ukip sources.
The divisions within Ukip have been exposed after Mr Farage was widely mocked for quitting as leader after failing to win the South Thanet seat he stood for in the general election, only to be reinstated three days later after the party's national executive committee (NEC) rejected his resignation.
Mr Wheeler, a former party treasurer who donated almost £100,000 (€138,000) to help fund Ukip's general election campaign, told BBC Radio 5 Live that Mr Farage should go.
He said: "I would like him to step down, at least for the moment. And if he wants to put himself up in an election, then he has every right to do so, though I personally would prefer somebody else now."
With the prospect of an in/out referendum on Europe, Mr Wheeler said: "The type of campaign that's now needed has to be slightly less aggressive and more towards winning over people in the centre".
Ukip treasurer Hugh Williams hinted that Mr Farage's leadership risked the party being seen as a one-man operation. He told BBC Radio 4's 'The World At One': "There has to come a time - and I think that time is probably now - when he has to let the party stand on its own two feet and become a party in its own right.
"Otherwise there is this danger, and it is obviously perceived by some to be a great danger, that it is seen as the Nigel Farage party rather than the UK Independence Party."
In an interview, Mr O'Flynn claimed Mr Farage had become a "snarling, thin-skinned, aggressive" man.
Mr Farage, speaking outside the party's London office, said: "If the NEC unanimously back me, that's not my fault, is it?"