Tony Blair has revealed he will "struggle" to back the Labour Party at a general election.
In an exclusive interview with talkRADIO, the former Labour Prime Minister said he was not the "world's greatest supporter" of Jeremy Corbyn.
"I’ve always voted Labour. I’m not going to pretend to you it’s not a struggle for me with my profound disagreement with the Corbyn leadership, but probably because of history, tradition, and because I am so passionately opposed to Brexit, I can see myself voting Labour," he said.
But he warned other Labour supporters may "go the other way".
"This is the problem for the Labour Party. There are a lot of people who are going to really struggle," he added.
His comments come after Boris Johnson announced he would pursue a general election on December 12.
But Mr Blair said he could not see any "possible rationale" for holding an election instead of a second vote on the UK's membership of the EU.
"If you're going to break the deadlock over Brexit through the people, tell me what possible rationale is there for doing that through an election and not a referendum?" he asked.
And he said he "can't trust" his successor on the issue of Brexit, accusing Mr Johnson of negotiating a "botched deal" with Brussels.
"Though I profoundly disagree with him on whether Brexit is a good idea, actually, Nigel Farage has produced one of the better analyses of what the problem is with Boris Johnson's deal," he said.
"The problem in the end is, if you really want to diverge on tax and regulation and go your own way on issues to do with trade... the only way you're going to get that is by doing no deal."
Labour Party policy is to hold a second referendum with a choice of a Labour-negotiated deal or remain.