Former Prime Minister Tony Blair has refused to confirm he would vote Labour at the next general election.
In an interview with BBC Newsnight, the ex-Labour leader was asked three times whether he would vote for the party amid rows on Brexit and anti-Semitism.
Mr Blair said the anti-Semitism crisis was "a real problem for me" and that he hoped the party "deals with it".
His comments come as Jeremy Corbyn vowed to speed up expulsions of members in response to criticism from MPs.
Mr Blair's former communications director, Alastair Campbell, was thrown out of the party in May after voting for the Liberal Democrats in the European parliamentary elections.
Labour has since adopted a new position on Brexit, backing another referendum in all circumstances and agreeing to campaign to remain in any vote on a Tory deal or no deal exit.
Asked if he too might consider voting Lib Dem, Mr Blair said: "I don't want to vote Lib Dem. I want to vote Labour. But I won't resile from the fact that the Labour Party is in a difficult situation at the moment, particularly with this anti-Semitism business."
He said anti-Semitism was "fundamentally repugnant to everything the Labour Party should stand for" and that if it wasn't sorted out "it's going to be a big problem".
Asked again whether he would be able to vote Labour in the current situation, he replied: "Let's hope the Labour Party seizes and grips this anti-Semitism thing and deals with it, because otherwise that's going to be a big problem."
Nine MPs and three peers have left Labour over its handling of anti-Semitism allegations among members.
At a meeting of the shadow cabinet on Monday, Mr Corbyn said the process for dealing with anti-Semitism complaints against party members was still taking too long and the "poison" of anti-Jewish racism had to be confronted.
Mr Blair said there would be "a moment to debate the state of the Labour Party," but that moment was not now. "We've got to deal with Brexit first," he told Emily Maitlis.
Mr Blair said Brexit was "not a reason for voting Labour or not voting Labour" and that he had always been in favour of Britain remaining in the EU.
He said the Conservatives were able "to behave with an almost surreal sense of irresponsibility at the moment because of the weakness of the Labour Party".
Such weakness "facilitates" right-wing politics, he added.