MPs have a “duty” to come up with an alternative to Theresa May’s Brexit deal, Scottish First Minister Nicola Sturgeon has said.
The prime minister is battling to win backing for her withdrawal plan ahead of a key vote in the Commons next week.
Ms Sturgeon said MPs have “a duty to decide what they want to do instead” to avoid leaving the EU without a deal.
She called for Labour to “come off the fence” and join other opposition groups in backing a new referendum on Brexit.
The UK government has insisted that “the plan is to win the vote” on Mrs May’s deal, and has opposed putting the matter back to the general public.
The Commons vote on Mrs May’s deal – which includes the legal framework for the UK’s exit from the EU, alongside a more political paper on the future relationship between the two – was postponed in December with the government facing a “significant” defeat. It is now expected to be held on Tuesday, 15 January.
With the UK due to leave the EU on 29 March under current legislation, the prime minister has sought to characterise the “meaningful vote” as a choice between her blueprint and no deal at all.
New work is under way to prepare for a no-deal exit, with a major exercise involving dozens of lorries currently being carried out in Kent to test how traffic queues around ports could be managed.
However more than 200 MPs have signed a letter to Mrs May urging her to rule out a no-deal Brexit, with both Leave and Remain supporters uniting against the idea of “crashing out without a deal”.
Speaking to the BBC’s Good Morning Scotland programme, Ms Sturgeon accepted that exiting without a deal is the “default option”, but said there was “no reason whatsoever” that voting down Mrs May’s plan would necessarily lead to this outcome.
She said: “It’s not enough for MPs to say they’re against the withdrawal agreement. MPs also have a duty to decide what they want to do instead.
“I hope the meaningful vote does go ahead next week so MPs can once and for all say they don’t support the withdrawal agreement, and then the House of Commons can coalesce behind the alternative.
“In my view that alternative should be to have another EU referendum.
“I don’t take for granted that there is a majority for that, but the SNP will be part of building that majority. And if we can get Labour to finally come off the fence and stop prevaricating, then we’ll be closer to building that majority.”
Ms Sturgeon said her party would push for any new referendum to include terms that would “ensure Scotland’s voice could be heard”, after 62% of Scottish voters backed Remain in the 2016 ballot.
She said: “We put forward a proposal last time round saying that the UK couldn’t leave the EU unless all four nations voted for that. We would seek to do that again.
“If we have another referendum and we have the same result – and I can’t guarantee that won’t be the case, I’m pretty confident Scotland would vote to remain – it simply underlines the position that I think became evident after 2016, that Scotland’s interests cannot be protected within the current setup in the UK.
“It does, as all of the events in my view the events in the last few years have done, is make the case for Scotland being an independent country in charge of our own destiny, even stronger.”
MPs are returning to Westminster after the Christmas recess ready to restart the debate over Brexit, with opposition to Mrs May’s proposal still in evidence both among opposition parties and on the government’s own back benches.
The Democratic Unionist Party, which the Conservatives rely on for a majority, has said there is “no way” it can back the deal as it currently stands.
Mrs May is understood to be preparing further reassurances on the controversial “backstop” plan, an insurance measure in the withdrawal blueprint which would avoid a hard border between Northern Ireland and the Republic of Ireland if the UK and EU are unable to strike a deal further down the line in the Brexit process.
Former foreign secretary and prominent Brexiteer Boris Johnson wrote in The Daily Telegraph on Monday that the backstop should be removed from the withdrawal agreement, and claimed that leaving the EU without a deal was “gaining in popularity” with the public.
But Mrs May warned on Sunday that the UK would be in “uncharted territory” if her deal is rejected.
Labour meanwhile have opposed Mrs May’s Brexit deal, and are focused on forcing a general election and a change of government at Westminster.
Shadow Foreign Secretary Emily Thornberry told the BBC’s The World This Weekend programme that those campaigning for a new referendum on Brexit should work on “changing people’s minds” about whether to leave the EU, rather than “smacking Labour around the head”.
The Scottish Conservatives accused Ms Sturgeon of being “stuck in the past” with her “independence obsession”.
Interim leader Jackson Carlaw said: “People across the country will correctly be thinking, ‘there she goes again’. Scots have had enough of Sturgeon’s stuck record on independence and just want the SNP to improve public services.”