In an interview with German newspaper Der Spiegel, Mr Corbyn dismissed calls to attempt to prevent Brexit, saying: “We can’t stop it. The referendum took place. Article 50 has been triggered. What we can do is recognise the reasons why people voted leave.”
Amid confusion over the party’s Brexit stance, Sir Keir pointed out that Labour’s official policy is to leave all options on the table, including a second referendum.
He told Sky News: “Brexit can be stopped. But the real question is, what are the decisions we’re going to face over the next few weeks and months?
“Decision one is on the deal; decision two is – if the deal goes down – should there be a general election? And decision three is – if there’s no general election – all options must be on the table, including the option of a public vote.
“That’s the clear position and Jeremy’s signed up to that, I’m signed up to that, and that was the position that was passed at Labour Party conference.”
Labour’s preferred option is to campaign for a general election but as the Brexit talks enter the chaotic final stages, the party is under pressure to soften its stance towards a new public vote.
Delegates at Labour’s conference in September, overwhelmingly backed a motion saying the party “must support all options remaining on the table, including campaigning for a public vote”.
Sir Keir also received a standing ovation when he told the conference hall that remaining in the EU could be on the ballot paper in a future vote.
But tensions remain over the issue, as influential figures such as Unite boss Len McCluskey and shadow chancellor John McDonnell are unenthusiastic about a rerun of the Brexit vote.
Mr Corbyn faced a backlash from his own MPs when he stood by his comments in the German newspaper and rejected calls for a Final Say referendum on Theresa May’s deal.
Sir Keir admitted there were some “slightly different voices” in Labour ranks but “everybody has coalesced” around a common position on Brexit.
“Insofar as he [Mr Corbyn] says the referendum took place, of course he is right about that,” he told the Today programme.
“But on this question of options on the table, we had a long, long discussion about it and we did agree all options to remain on the table, including the option of a public vote.
“Neither Jeremy nor anyone else has altered that position, that is the position of the Labour Party.”
He added: “The Labour Party has a healthy discussion. But did we reach an agreement? Yes we did. Are we sticking to it? Yes we are.”
It comes as hopes of getting a deal within the next 48 hours were fading amid an apparent impasse between Brussels and London.
Ms May’s key Brexit adviser Olly Robbins held talks with counterparts in Brussels over the weekend but the prospect of securing a November summit to rubber-stamp the deal is looking more unlikely.
Michel Barnier, the EU’s chief Brexit negotiator, is due to address EU ministers at a general affairs council meeting later on Monday.
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