None of the Ukip leadership candidates is good enough to rescue the party from its crisis, its biggest donor has suggested.

Arron Banks dismissed the abilities of all four remaining candidates pitching to take over Ukip later his month, criticising them for wanting to “push it to the centre”.

Mr Banks also suggested his close ally Nigel Farage could return again as leader to stabilise the party, particularly if Theresa May backtracks on Brexit.

And he hinted he could be a leadership candidate at some point in the future, noting that he was not in the running “at the moment”.

Paul Nuttal, a North West MEP, Suzanne Evans, the party’s deputy chairwoman, London Assembly member Peter Whittle, and John Rees-Evans are the four candidates.

Mr Banks had backed Raheem Kassam, Mr Farage’s former chief of staff, who quit the leadership race earlier this week, citing a lack of support.

Today, he said: “We’re struggling at the moment, there’s no point in denying it – I think I’ve backed something like two or three different leaders in the space of three months.

“At the moment, I’m struggling with the candidates on offer.”

Mr Banks predicted Mr Nuttal will win, but warned he did not have the strength to carry out the badly-needed clearout of troublemakers in the party.

Speaking to BBC Radio 4’s Today programme, he said, of Ukip “it’s got to be neither right, nor left, it’s got to be radical and it’s got to be anti-establishment”.

And he said: “My problem with all of the candidates is that they seemingly want to push it to the centre which seems a ludicrous place for it to be.”

Asked if Ukip was finished, Mr Banks added: “It could be - it's at a crossroads.

“I don't know if it's over for Ukip. It's certainly achieved its main goal in politics, which was to get the [EU] referendum and win it.”

Since October 2014, Mr Banks and Rock Services, of which he is a director, have donated more than £1.25m – but he has warned that he may never give it money again.

Steven Woolfe, the early frontrunner in the leadership contest and Mr Banks’s first preferred candidate, bowed out and quit the party altogether.