The Labour Party will exploit division within the Conservatives and call on Tory rebels to support parliament having a final say on Brexit.
The party will urge Tory MPs on Wednesday (13 December) to accept changes to the EU Withdrawal Bill, which would give parliament the chance to have a meaningful vote on the terms of leaving the European Union.
Already 20 Tory MPs have signed a similar amendment requiring primary legislation to approve the withdrawal bill, which is significant given that only seven rebel Tory MPs would be enough to defeat the government's majority.
Dominic Grieve, a former attorney general, said the prime minister is facing the "real possibility" of a defeat over the issue.
Matthew Pennycook, shadow Brexit minister, said Tory rebels need to go further to ensure that parliament and not MPs to have the final say on Britain's Brexit deal.
"Warm words and woolly concessions from ministers are not enough. Tory MPs must now make a choice about whether they will allow ministers to press ahead with their fatally flawed withdrawal bill or accept Labour's sensible demands to ensure Parliament has a meaningful role."
"Tory rebels have talked the talk, now they must walk the walk," he said, in a statement.
In response to the rancour among Tory back benches, the prime minister, Theresa May, said: "There are obviously colleagues who are concerned about processes in the House of Commons, and are looking for reassurance around the Withdrawal Bill, and we have been listening and talking to those colleagues."
Sticking points remain, especially after Brexit secretary, David Davis, was accused by Brussels of damaging trust by his comments that the agreement reached with the EU last week had no legal status. Also, Michel Barnier, the EU's chief negotiator, said any Brexit deal depended on keeping the interim agreement already made, adding "we will not accept any backtracking from the UK".
Britain's defence commitments
But a new report by the the think tank the Henry Jackson Society, says that the EU will need British military support in future and this should be a factor in negotiations with Brussels.
The report titled What the European Union owes the United Kingdom, shows that EU countries that are also in NATO, have "shortchanged" the alliance by $451bn (£338bn) between 2012 and 2016.
It said that British defence spending over this time of US$285.5bn (£214bn) comprises almost a third (32%) of spending by countries in both NATO and the EU and illustrates how the UK has effectively subsidised the security and defence of the European mainland by an extra US$23.9bn.
Author of the report, James Rogers, said that there needed to be a "new and durable relationship" between the UK and the EU.
"The United Kingdom has been disparaged by many Europeans for its decision to leave the EU. Some have gone so far as to construct it as a kind of pariah state. This depiction is entirely unwarranted.
"Britain remains deeply committed to the security of Europe as the largest European military and foreign aid spender. Moreover, most European countries, insofar as they have short-changed both NATO and the world's poorest people by hundreds of billions of dollars over the past five years, have their own shortcomings, which should not be overlooked," he said.