Nigel Farage has said UKIP will make sure every household in Clacton is asked whether they want a by-election after Douglas Carswell quit the party.
UKIP's only MP said he was leaving the party after the success of the Brexit referendum, but would continue to sit in the Commons as an independent.
Despite Mr Carswell's insistence his departure was amicable, he has faced a barrage of criticism from former party colleagues, who are demanding he trigger a by-election.
Mr Farage, who had a fractious relationship with Mr Carswell, told Sophy Ridge on Sunday: "This a guy who also sells himself as being very honourable and different from anybody else.
"One of his big crusades in Parliament has been recall, real recall. The way he himself has said it is that if 20% of constituents want a by-election they should have one.
"So what we are going to do, to show how honourable he is, we are going to write through the Electoral Reform Society to every house in Clacton and ask people whether they want him, as he's moved, to stand for a by-election."
Farage said the MP has been "working against" the party and seemed to dismiss his electoral success.
"He has got the most Euro-sceptic constituency in the country. Out of all 650 seats, Clacton is the constituency that UKIP could win," he said.
"He never, ever believed in the principles that UKIP believe."
In an interview with Sky News, Mr Carswell denied he joined the party to undermine the former leader and said he wished Mr Farage well.
"I haven't spoken to him (Nigel Farage) for a long time, one of those by-elections that we lost... that was about the last time we spoke.
"But you know I wish Nigel well and I just wish he would be a bit more positive about the fact that on Wednesday, we win."
Although, the Clacton MP has ruled out a return to the Conservative Party for now, current UKIP leader Paul Nuttall described him as at heart a Brexit-supporting staunch Tory.
Speaking to Sky News, he said the party was calling for a by-election in Mr Carswell's Clacton seat and added: "I'm disappointed when anyone leaves UKIP whether at a grassroots level or whether it's at parliamentary level.
"However I'm not surprised, Douglas and UKIP have been drifting apart for quite a while now."
Mr Carswell was first elected to represent Clacton in 2005 as a Conservative MP, but defected to UKIP in 2014 and subsequently won the by-election as the party's only MP.