Theresa May has warned MPs that the country will be plunged into “uncertainty and risk” if her Brexit deal is rejected.

Mrs May was jeered by opposition MPs as she said it would not be in the “national interest” to block the Government’s agreement with the EU.

The Prime Minister made the comments as she kicked off a five-day Commons debate ahead of the December 11 “meaningful vote”.

Labour leader Jeremy Corbyn dismissed the PM’s suggestion however and said the deal had put the country “over a barrel”.

Mrs May said: “Don’t imagine that if we vote this down another deal is going to miraculously appear.

“The alternative is uncertainty and risk; the risk Brexit could be stopped, the risk we could crash out with no deal.”

Mrs May, after suffering three humiliating Commons defeats in little more than an hour, also appeared to soften her approach to Parliament as she pledged to give MPs a “greater and more formal role” in the UK’s forthcoming negotiations with the EU over future trade.

Mrs May said she wanted to launch a “national mission” to forge the “strongest possible future relationship” with the EU.

She said: “I want to build the broadest possible consensus both within this House and across the country, so for the next stage of negotiations we will ensure a greater and more formal role for Parliament.

“This will begin immediately as we develop our negotiating mandate building on the political declaration ahead of 29 March 2019. The Government will consult more widely and engage more intensively with Parliament as we finalise the mandate for the next phase of the negotiations.”

Theresa May
Theresa May speaks in the Commons (PA)

Mrs May said the Commons would be “consulted” on the outcome of negotiations – but in response to a question from Labour MP Hilary Benn, who chairs the Commons Brexit Committee, she did not go as far as to pledge MPs would have a vote.

Mr Corbyn later said the Prime Minister had achieved something “extraordinary” with her Brexit deal: “Across this House it has achieved something – it has united both Conservative Remainers and Conservative Leavers and members of every opposition party in an extraordinary coalition against the deal.

“Following the 2017 election, the Prime Minister could have attempted to build a consensus, recognising the new arithmetic of Parliament, and sought a deal that brought people together.

“Instead, just like her predecessor – who called a referendum without preparing for the eventuality of a Leave vote – the Prime Minister has seen these negotiations only as an exercise in the internal management of the Conservative Party.”

He added: “This Government is not taking back control, it is losing control.”

“We are over barrel, either paying whatever is demanded or negotiating away fishing rights, who knows what else? This is a terrible failure of negotiation by this Government,” he added.

SNP Westminster leader Ian Blackford berated the PM’s Brexit plan for “pulling up the drawbridge” on EU nationals.

He also said the UK Government had treated Scotland with contempt and predicted Scotland will become an independent country.

Mr Blackford said: “The Tories think they can do whatever they want to Scotland and get away with it, they think they can railroad this deal against our will and against our interests, the mask has well and truly slipped for the Tories.

“Let me say this, Scotland is not a second class nation and our people do not deserve a second class deal. This proposed deal is a non-starter and a no-deal Brexit is unthinkable.

“That means the priority now must be to stop Brexit and the SNP has made clear we will support any steps which would secure Scotland’s place in the EU in line with the votes of the people of Scotland.”