Theresa May will face the Commons for the first time since the EU rejected her Brexit plan, amid mounting pressure from some Tory MPs to change course.
A week before a crucial meeting of EU leaders, the prime minister shows no sign of abandoning her proposals.
Former Brexit Secretary David Davis has warned of “dire” electoral consequences for the party if she persists with her model for trade with the EU.
But ministers say the UK and the EU are “closing in on workable solutions”.
Despite the UK’s imminent departure from the EU in March 2019, there is not yet a deal between the two sides on how separation will work and what their future relationship will look like.
Intense negotiations are taking place to try to reach a compromise by November – with the EU set to assess the progress made at a European Council summit next week.
One of the major sticking points has been how to avoid new checks on the border between Northern Ireland and the Irish Republic, which will also become the future frontier between the UK and the European Union.
Mrs May has been warned by Northern Ireland’s Democratic Unionist Party – whose support she relies on in key votes in Parliament – that it will not accept any solution that “divides” the UK down the Irish Sea.
At last month’s Salzburg summit, EU leaders rebuffed the PM’s plan for a free trade zone for manufactured and agricultural goods, underpinned by a common rule book, and a combined customs territory – the so-called Chequers plan.
Then, at the Conservative Party conference in Birmingham last week, rows over her strategy loomed large, with critics including former Foreign Secretary Boris Johnson urging her to “chuck” it in favour of a free trade deal like the EU has with Canada.
In a letter to fellow Tory MPs, Mr Davis said a deal based on Mrs May’s Chequers plan would deliver “none of the benefits of Brexit” and reduce the UK to being “a rule-taker from Brussels”.
Speaking in the Commons on Tuesday, Brexit Secretary Dominic Raab, said differences remained between the UK and EU on the withdrawal agreement but insisted “we are closing in on workable solutions”.
He also told MPs that the UK would not remain tied to the EU’s customs union indefinitely – an attempt to reassure Tory Brexiteers who have warned they have the numbers to vote down any final Brexit deal that they don’t agree with.
Mr Raab stressed the need to “hold our nerve” and “stay resolute” to secure a good deal – but played down suggestions of a breakthrough.
After Tuesday’s weekly cabinet meeting, Downing Street made clear Mrs May would not agree to any withdrawal deal, including the £39bn so-called divorce bill to be paid to the EU, without a “precise” declaration of the two sides’ future trade and security partnership.
Meanwhile, the International Monetary Fund (IMF) has warned that a disorderly Brexit could threaten the stability of the world economy.
The US-based organisation said a “no-deal” departure from the EU could lead to fragmentation in European money markets, meaning finance cannot flow around the system so efficiently.
The IMF has urged the Bank of England to be ready to provide more quantitative easing – creating new money – if it is required.