Nigel Farage has said Leave campaigner Arron Banks has "given up" on fighting the Tories over Brexit as he has got "Brexhaustion".
The Brexit Party leader said Mr Banks, co-leader of the Leave.EU campaign, has "had enough of Brexit".
Mr Farage added that the Brexit Party must continue its fight to "make sure we get a proper Brexit".
Responding to Mr Banks' comments that it is "time to take the chips off the table" and get behind the Conservative Party to deliver Brexit, Mr Farage said: "You're right, he (Arron Banks) has given it up."
Speaking on Radio 4's Today programme, Mr Farage added: "Look, Arron Banks has never given a penny to the Brexit Party, let's be clear about that, he's not supported the Brexit Party.
"He, I think, has just had enough of Brexit, it's Brexhaustion, and he's happy – he was happy, for some reason – to go along with Mrs May and Boris's deal.
"What we've got so far in this campaign is for Boris to promise to change direction, what we now have to do is to hold him to account to make sure we get a proper Brexit, and that's my job."
Mr Farage's revealed earlier this week that the Brexit Party would not contest the 317 seats won by the Conservatives in the last election.
But he insisted he will stand candidates in Labour-held marginal seats, despite coming under pressure from the Conservatives to step aside.
Discussing the Tories' refusal to stand aside in Labour marginal seats, Mr Farage said the Conservatives would rather risk losing the election than forming a Leave alliance with his party.
He said: "This all started way back in September when I sent to Number 10 some polling that said that in their 40 key seats, if I endorsed their Conservative candidate, one-third of Labour voters in those seats would vote Conservative on a one-off basis to get a genuine Brexit done.
"And ever since that time, what I've realised is that the Conservatives want a Conservative majority in Parliament, not a Brexit majority in Parliament.
"There are very clearly seats in which we are the lead challenger and there are other seats in which they are the lead challenger to Labour, and we could have done a deal on that basis, but the priority for the Conservative Party, they do not want the Brexit Party to get seats in Parliament.
"They'd rather risk not winning the election than having a Leave majority, a Leave alliance."
Mr Farage also said he believes tactical voting will decide the General Election.
He said: "I'm going to go out around the country saying to Labour voters, 'you are being let down badly, betrayed by the Labour Party who now want you to vote again'.
"And the same for Conservative voters, in seats that the Conservatives have never won in 100 years, your best chance of getting Brexit is to get us in there and hold Boris Johnson to account.
"And ultimately this election will be decided by tactical voting decisions all across the country."