Pic-MPs are due to restart the debate on Mrs May's Brexit deal on Wednesday before a vote next week/bbc
Political reporter(wp/bbc):
Theresa May has said the Commons vote on her Brexit deal will "definitely" go ahead next week.
She told the BBC she was seeking assurances from the EU to address the concerns of MPs, as well as specific measures relating to Northern Ireland.
She also said she would look at giving Parliament a greater say in how the UK's future relationship is negotiated.
But a poll carried out for the People's Vote campaign suggests fewer than one in four voters support her Brexit deal.
MPs are due to vote on whether to back Mrs May's Brexit plan in the next two weeks.
Asked by the BBC's Andrew Marr if the vote - which was postponed last month - would go ahead, she replied "definitely".
She said the UK would be in "unchartered territory" if the Commons rejected the terms of the UK's withdrawal but asked repeatedly if she would seek further votes if this happened, she declined to say.
The UK is due to leave the EU on 29 March 2019 - regardless of whether there is a deal with the EU or not.
A deal on the terms of the UK's divorce and the framework of future relations has been agreed between the prime minister and the EU - but it needs to pass a vote by MPs in Parliament before it is accepted.
The House of Commons vote had been scheduled to take place in December but Mrs May called it off after it became clear that not enough MPs would vote for her deal.
The debate on the deal will restart on Wednesday, with the crucial vote now expected to take place on 15 January.
Writing in the Mail, Mrs May said: "The only way to both honour the result of the referendum and protect jobs and security is by backing the deal that is on the table."
She said "no one else has an alternative plan" that delivers on the EU referendum result, protects jobs and provides certainty to businesses.
"There are some in Parliament who, despite voting in favour of holding the referendum, voting in favour of triggering Article 50 and standing on manifestos committed to delivering Brexit, now want to stop us leaving by holding another referendum," she said.
"Others across the House of Commons are so focused on their particular vision of Brexit that they risk making a perfect ideal the enemy of a good deal.
"Both groups are motivated by what they think is best for the country, but both must realise the risks they are running with our democracy and the livelihoods of our constituents."
Public polled on Brexit
Meanwhile, a poll of more than 25,000 Britons suggests Labour would be punished by voters if the party either ends up backing the government's deal or does not actively oppose it.
The YouGov poll, carried out for the People's Vote campaign which is demanding another referendum, suggests 75% of Labour supporters would prefer a final say on Brexit.
Shadow Health Secretary Jonathan Ashworth told the BBC's Andrew Marr Show that it was completely wrong to suggest, as some have done, that Labour was "enabling Brexit".
"This country had a referendum," he said. "The British people voted in that referendum for Brexit."
Labour, he insisted, had decided as a party not to rule out any options but, if the PM's deal was rejected, the government needed to choose what to do next and potentially re-open the negotiations.
The poll also suggested:
- 22% of all Britons back Mrs May's deal, rising to 28% among Leave voters
- 53% of Britons believe they - instead of MPs - should be given the final say on Brexit, once those who responded "don't know" were removed
- And among those who said they would vote in another referendum, the survey suggested 54% would back remaining in the EU, compared to 46% for Leave
Mrs May now has less than a fortnight to persuade Parliament to back her deal.
Some Conservative MPs continue to believe the deal does not represent the Brexit the country voted for in 2016 - with some happy for the UK to leave the EU with no deal.
"If there has been a change it is a hardening of attitudes among MPs to a no deal," Peter Bone told the Sophy Ridge show on Sky News.
He said there was increasing evidence that a no deal was "absolutely OK".
The best way to "get on" with Brexit was to leave without a deal, he added: "There was no question I remember in the referendum about a deal or not. It was leave or remain. The way you leave is to come out on March 29."
Other MPs are pushing for a second referendum, while opposition parties including Labour plan to vote against her deal.
Labour wants to force a general election by calling a vote of no confidence in the government if the deal is rejected by MPs.
Mrs May has been seeking further assurances from EU leaders about more controversial aspects of the agreement such as the Irish border "backstop", which is designed to prevent physical customs checks on the island of Ireland.
The Democratic Unionist Party - whose support the Conservative Party relies on for a majority in the House of Commons - wants to make sure the backstop is temporary and that the UK, including Northern Ireland, can exit from it without EU approval.
