The defection of Clacton MP Douglas Carswell to the UK Independence Party is one of the biggest single events in the history of the party, leader Nigel Farage has claimed.

He said anything would be possible in May if the eurosceptic former Tory fought the by-election and won it this year.

Following an announcement at a London press conference this morning, Mr Farage said that they should “get on with it” and hold the ballot quickly. Mr Carswell said he was standing down as an MP to give voters a say after he has left the Conservative Party to join UKIP.

Speaking to the EADT immediately after Mr Carswell made the announcement, Mr Farage said: “For those who criticise what he (Mr Carswell) has done, do you know what, they will get a chance in a by-election to have their say.

“I think the MP has stood down and said judge me and I think we should get on with it.”

“I think is one of the biggest single events in the history of UKIP. This is a hugely significant moment for our party as a political force in Britain.

“I think if you look at the Conservative Party’s membership figures in Clacton, which have been going up at the same time they have been spiralling downwards across the rest of Britain, there is some evidence that a lot of that Conservative vote in Clacton it in fact a personal vote for Douglas Carswell.”

He said he expected the by-election to happen as quickly as the end of September, but it could take a little bit longer.

Questioned on whether there were other MPs who could also jump over UKIP, he said: “There is no way anybody will think Douglas Carswell is an isolated individual eccentric member of parliament. We all know there are quite a lot of other backbench Conservative, and indeed Labour MPs, thinking the same way.”

He added: “Obviously the East of England is a very strong eurosceptic part of Britain, but this is more about him as a person than about the East of England. This is about him as a person saying I am going to do something about principle, and a point of honour.

“He has got a big majority, he had got a big personal rating. If you had put a UKIP candidate up against him next year, I’m sure he would have won handsomely.”