Boris Johnson will attempt to persuade MPs to back his Brexit deal today ahead of what is expected to be a knife-edge vote in the Commons on Saturday.
Mr Johnson has insisted he is “very confident” MPs will back his deal.
But the DUP’s opposition to his plans means he faces a battle to get the agreement through Parliament.
The PM is expected to focus his attention on Labour MPs in Leave-voting areas, a group of Tory Brexiteers, and rebels he expelled from his party.
Conservative Party chairman James Cleverly said conversations with the Democratic Unionist Party would also continue, despite their insistence they would oppose the deal.
Saturday’s showdown in the Commons is the prime minister’s last chance to get Parliament to approve a deal before the Brexit deadline of 31 October.
If MPs reject his plans, legislation passed by MPs says he must ask the EU for an extension until 31 January 2020 – something he has repeatedly insisted he would not do.
The BBC’s political editor, Laura Kuenssberg, said she understood the government would try to sidestep a delay and push for a general election if it was defeated on Saturday.
The revised Brexit agreement between the UK and the EU was announced at a summit of European leaders on Thursday.
Hailing the “excellent deal”, the prime minister urged MPs to “come together” to vote for his plans and “get Brexit done”.
But the DUP – whose support was seen as highly important for getting a deal through Parliament – said it would oppose the plans over concessions made by the UK to the EU on customs checks at points of entry into Northern Ireland, among other issues.
Opposition parties also confirmed they would reject the deal and instruct their MPs to vote against it.
As a result, the prime minister is expected to focus his attention on three groups:
- Tory Brexiteers who have not yet backed a deal and repeatedly voted against former PM Theresa May’s withdrawal agreement
- Twenty-three former Tory MPs who now sit as independents, including 21 Mr Johnson kicked out of the party last month after they rebelled against him in a bid to prevent a no-deal Brexit
- And a group of Labour MPs who have expressed a desire to back a deal but are concerned about protection for workers and the environment
One of these MPs, Ronnie Campbell, told the BBC’s Newsnight he was minded to defy his party and back the deal.
“I think this country’s just fed up with the way Parliament’s run this for the last three years,” said the Labour veteran, who is standing down at the next election.
BBC political correspondent Nick Eardley said he understood Labour MPs who rebelled by backing Mr Johnson would not lose the whip, that is, not be effectively expelled from the party.