Nigel Farage’s UK Independence Party (UKIP) has stormed into the lead in the British parliamentary constituency of Clacton – an area which will play host to a by-election soon following the defection and resignation of the sitting Member of Parliament Douglas Carswell.

Earlier this week Mr Carswell and Mr Farage rocked the Westminster village by announcing the former’s defection from the Conservatives to UKIP. A Mail on Sunday poll conducted by Survation showed that UKIP currently lead the Tories by 64 points to 20 – an unprecedented 44 point lead.

Labour come in third on 13 percent, while the Liberal Democrats may as well not stand a candidate at all, gaining just two percent of the vote share.

But perhaps the most interesting part of the Mail’s poll is the question about how voting intention would change if Boris Johnson were to stand against Carswell.

In this scenario, UKIP loses just 4 points out of 64, and the Tories actually gain the same number (4) from Labour and the Lib Dems combined as they do from UKIP. A Carswell vs. Johnson election would lead to Carswell winning by 60 points against 27. 

Far from the issue being one of local celebrity for the incumbent MP, 57 percent of respondents claimed they’ve vote for him because they like UKIP. Just 34 percent said they were following the Carswell celebrity. 

The Mail notes that if the results are borne out in the by-election, it would reflect the largest post-war electoral swing ever. 

Damian Lyons Lowe, Chief Executive of polling firm Survation said: “Mr Carswell has been accused of betraying his party, but that is not how the vast majority of his constituents see him.  

“Today’s survey lays to rest the notion that Mr Carswell defected for cynical reasons after becoming convinced that if he didn’t, he would lose to Ukip.

“Such is his personal popularity that he would almost certainly have won the seat had he fought it with a blue rosette next May, rather than now in the yellow and purple colours of Ukip. 

“Most worrying of all for the Prime Minister is the reaction of other potential Tory MP defectors to the likely outcome of the by-election.”