Theresa May has attacked one of her predecessors - accusing Tony Blair of "undermining" the Brexit talks by calling for another referendum.
She called his comments an "insult to the office he once held" and said MPs could not "abdicate responsibility" to deliver Brexit by holding a new poll.
Blair said MPs might back a new vote if "none of the other options work".
It comes after Labour MPs who support the idea met Cabinet Office Minister David Lidington to make their case.
About 10 MPs met Lidington on Thursday to argue for another public vote and make it clear there was no other government plan they could support.
But many senior Labour figures are deeply uneasy about endorsing another referendum.
And the government is opposed to any further referendum, saying the public made a clear choice when they voted in 2016 to leave by a margin of 51.9 per cent to 48.1.
BBC political correspondent Chris Mason said May's criticism of Blair was striking for its anger.
May said: "For Tony Blair to go to Brussels and seek to undermine our negotiations by advocating for a second referendum is an insult to the office he once held and the people he once served.
"We cannot, as he would, abdicate responsibility for this decision.
"Parliament has a democratic duty to deliver what the British people voted for."
She added that there were "too many people who want to subvert the process for their own political interests - rather than acting in the national interest".
MPs were due to vote on May's Brexit deal on Tuesday, but it was postponed when the prime minister admitted it would have been "rejected by a significant margin".
After postponing the vote in Parliament, May travelled to Brussels to make a special plea to EU leaders, in a bid to make her deal more acceptable to MPs.
However, the EU said there could be clarification but not renegotiation.
Many of May's MPs are concerned that the "backstop" - which is aimed at preventing a hard border in Northern Ireland - would keep the UK tied to EU rules and limit its ability to strike trade deals.
Meanwhile, in an interview with the Sunday Telegraph, Foreign Secretary Jeremy Hunt has said the UK will "flourish and prosper" even if it leaves the EU with no deal.
"We've faced much bigger challenges in our history," he said.
"But we shouldn't pretend that there wouldn't be disruption, there wouldn't be risk, and there wouldn't be impact and that's why as a responsible government we have to make all the preparations necessary."
He also said he wanted a "crack" at succeeding Mrs May after the PM takes the country through "this challenging next few months".
His comments come after Mrs May made it clear she would step down before the next general election - due in 2022.