British Prime Minister Theresa May and senior cabinet ministers are engaged in intensive discussions with MPs from all sides of the Brexit debate, as May fights to find a deal that could command support in parliament.
But opposition Labour leader Jeremy Corbyn and his front bench have continued to snub the talks, which Corbyn dismissed as a "stunt".
In a speech in the marginal Conservative constituency of Hastings, Corbyn called on May to ditch her negotiation red lines and take the prospect of a no-deal Brexit off the table.
"She seems to be prepared to send the country hurtling towards a cliff edge," he said on Thursday.
"To get a deal that can command a majority in parliament, Theresa May has to ditch the red lines and get serious about proposals for the future."
But Liberal Democrats accused the Labour leader of "playing political games" and said he could no longer rely on their support in future no-confidence votes, after he failed to throw his party behind calls for a second EU referendum.
A new opinion poll showed a 12-point lead for staying in the EU if a fresh referendum was held.
The YouGov survey for the People's Vote campaign, conducted after May's Brexit plan went down to a humiliating defeat in the House of Commons on Tuesday, put Remain on 56 per cent against 44 per cent for Leave.
After seeing off a vote of no-confidence in her government on Wednesday, May invited the other party leaders for individual talks to find a way forward on Brexit.
But she told the House of Commons she was holding to the "principles" behind the withdrawal agreement that was roundly rejected by MPs on Tuesday, including control of borders, laws and money and an independent trade policy.
The British parliament will debate and vote on May's "plan B" on January 29.
The EU's chief negotiator Michel Barnier indicated that Brussels was ready to respond to any revision of May's "red line" demands, telling MPs in Portugal, "if they change, we'll change".
Barnier said getting an agreement was "in everybody's interest" and that "something has to change" to secure a divorce deal.
Labour's former prime minister Tony Blair said Corbyn was wrong to snub the talks.
"If, in a moment of national crisis, the prime minister asks the leader of the opposition to come and talk, of course he should," Blair told BBC Radio 4's Today.
And Conservative chairman Brandon Lewis accused Labour of "trying to frustrate and avoid Brexit" by keeping open the option of a referendum.
May has said that "the door remains open" to Labour for talks ahead of the deadline for her to present her plan B to MPs on Monday.
Australian Associated Press