It comes as Theresa May met with cabinet members ahead of the high-stakes votes
Downing Street says the planned vote on the Brexit withdrawal deal will go ahead on Tuesday - despite a series of meetings between the British prime minister and cabinet ministers.
Theresa May's government looks on course for a heavy defeat when members of the House of Commons vote on the EU withdrawal agreement after five days of debate.
Pro-Brexit ministers such as Michael Gove and Andrea Leadsom were summoned to Downing Street today as the crucial vote fast approaches.
Details of the talks were not immediately apparent.
This week saw Mrs May's government put under further pressure over the Brexit deal, after they were reluctantly forced to publish legal advice on Brexit after being found in contempt of parliament.
The deal continues to be opposed by Labour, the DUP and even members of Mrs May's own Conservative party.
Graham Brady chairs the 1922 committee of backbench Conservative MPs in Westminster.
He says a delay would be 'perfectly sensible', unless Theresa May has a solution to concerns about the Irish backstop.
He argued: "I don't think there's any point in plowing ahead and losing the vote heavily.
"What I would like is to have the reassurance necessary that will answer the concerns that colleagues have - and if that can be done by Tuesday, that's fine."
Meanwhile, British chancellor Philip Hammond has warned MPs that there would be major economic consequences to a no-deal Brexit - saying he does not believe the country could afford the economic cost of a no-deal situation.
He highlighted potential tariffs on the likes of meat, clothing and cars, and said it would mark the end of 'frictionless trade' with the UK's biggest export market.
Earlier, Theresa May warned that a Brexit deal is impossible without the Irish border backstop - the aspect of the agreement that has drawn the most public criticism from Tory rebels and the DUP.