Labor is not ruling out remaining in the EU, says shadow Brexit secretary Sir Keir Starmer.
Labour is not trying to "frustrate" the process of leaving the European Union despite keeping open the option of a referendum on remaining in the bloc, the shadow Brexit secretary has said.
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Sir Keir Starmer was given a standing ovation at the Labour Party conference as he confirmed that the possibility of ditching Brexit could be in any future referendum called on the outcome of the process.
The Labour frontbencher indicated the party was set to vote against Theresa May's Brexit plan when it is put to a vote in the House of Commons and said it should trigger a general election if the Prime Minister was unable to win the approval of Parliament.
And he set out his support for the option of a referendum if no general election is called - a policy delegates at the conference will vote on later on Tuesday.
Sir Keir, who has confirmed he would vote to stay in the EU in any future referendum, said he was "devastated" by the 2016 Brexit vote.
Around two-thirds of delegates got to their feet to applaud the key passage in Sir Keir's conference speech as he set out Labour's approach.
Sir Keir said that if Labour could not secure a general election "we must have other options".
"That must include campaigning for a public vote," he said.
"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."
Explaining Labour's strategy for the looming Commons showdown on whatever deal Mrs May brings back from Brussels, Sir Keir said there was "division, chaos, failure" under her premiership and "the Government has no credible plan for Brexit, weeks out from the deadline".
"The Tory civil war on Europe that has been going on for years now risks our prosperity," he said.
"The party that once promised that it would fix the roof while the sun was shining is now intent on burning the whole house down.
"So I've got a message for the Prime Minister: if your party wants to tear itself apart, that's fine ... but you're not taking our country with you."
It is "increasingly likely" that whatever plan Mrs May brings back to the Commons will fail to meet Labour's tests for a Brexit agreement and if so "we would vote against her deal", he added.
Labour would also vote down a "vague" deal, a so-called "blind Brexit" that did not spell out details of the future relationship.
"This is not about frustrating the process," he said. "It is about stopping a destructive Tory Brexit."
Sir Keir refused to accept that the only option available if Mrs May's plan was voted down was a no-deal Brexit.
"No deal would be a catastrophe and no government has the right to plunge our country into chaos because of their own failures," he said.
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".
The possibility of another referendum after 17.4 million voted to leave the EU has led to fears of civil unrest and the rise of far-right politics.
But Sir Keir said that could be avoided and the party had a responsibility to save the UK from leaving without a deal.
Ahead of his speech, he told BBC Radio 5 Live a no-deal Brexit would "rupture our trading arrangements and this will cost jobs, I don't doubt that the pound will begin to drop".
"We won't have any arrangements for security and counter-terrorism - I worked, when I was director of public prosecutions, on counter-terrorism work across Europe - the idea that we wouldn't have an arrangement in place for that would horrify people," he said.
"And, frankly, this idea that we might have medicines stockpiled for six weeks has spooked people.
"We don't want to face that situation and we have got a duty to do something to stop it and that's why the option of a public vote is important as something that may have to happen when we get to that stage."
Acknowledging the sensitivity of the issue, he said: "We have to manage it in a sensible way but we have to accept we are only having this discussion because of the failure of the talks."
Labour's position leaves the Prime Minister brutally exposed to a rebellion by restive Tory backbenchers, with fewer than a dozen able to fracture her fragile control of the Commons in the upcoming vote.
Sir Keir confirmed talks are taking place with potential rebels, telling the BBC: "I think, if we get to that stage this autumn, most MPs would be prepared to say 'we need to do something to prevent us crashing out of the EU without a deal'."