Labour is not ruling out an option to stay in the EU in a second Brexit referendum, Sir Keir Starmer has told his party's conference in Liverpool.
The shadow Brexit Secretary won a lengthy standing ovation from Labour delegates for opening the door to the UK staying in the EU if the opposition cannot force a general election.
Around two-thirds of delegates got to their feet to applaud the key passage. Mr Starmer said that if Labour could not secure a general election "we must have other options".
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In an unscripted addition to his speech, which was not part of the version briefed to journalists, he said: "That must include campaigning for a public vote. It is right that Parliament has the first say but if we need to break the impasse, our options must include campaigning for a public vote and nobody is ruling out Remain as an option."
It follows confusion over Labour's stance on a second EU referendum after the Shadow Chancellor John McDonnell initially ruled out an option to stay in the bloc. The Unite general secretary Len McCluskey also came out strongly against any bid to stay in the EU.
Under the terms of the motion set to be voted on at the conference on Tuesday, if Labour cannot force an early general election it will "support all options remaining on the table, including campaigning for a public vote".
Earlier, Mr Starmer told the BBC: "There isn't this difference of opinion between me and John McDonnell and the whole Labour Party is united around the motion that is going forward this morning."
Labour appears set to reject Theresa May's Brexit plan, claiming it fails to meet the party's tests for any deal.
"Looking at the state of the negotiations, which are frankly chaotic and failing, it looks like she is not going to meet those tests so in those circumstances we will vote against a deal that she brings back," Mr Starmer added.
Labour MP Alison McGovern, who has campaigned for her party to back a so-called People's Vote, said: "When Keir Starmer says Labour must campaign for a public vote with remain as an option and he gets standing ovation from our party, you know just how far we’ve come in the past few weeks."
Conservative Party chairman Brandon Lewis said Labour were planning on taking the UK "back to square one on Brexit".
“In the space of one morning, he has refused to rule out delaying Brexit, refused to confirm Labour would end freedom of movement, and opened the door to staying in the EU with a second referendum," Mr Lewis said. "Labour’s promises on Brexit aren’t worth the paper they’re written on."
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The SNP's Europe spokesman, Stephen Gethins MP accused Labour of "playing games" and called on the party to take a clear stand against any Brexit deal that takes the UK out of the EU single market and customs union.
“It’s time for Labour to stop playing games and finally nail its colours to the mast with a genuine alternative to a Tory extreme Brexit," Mr Gethins said.
“Jeremy Corbyn’s shameless ‘man without a plan’ political posturing is simply not good enough."