The prime minister will hold a cabinet meeting on Tuesday amid growing anticipation that the UK and the EU could be on the verge of agreeing a deal on the Northern Ireland protocol.
But Sunak is facing up to a potential battle with members of his own party as he seeks to satisfy the demands of both Conservative MPs and Northern Ireland’s Democratic Unionist Party (DUP) over any agreement.
The European Research Group (ERG), a band of eurosceptic Conservative MPs, are expected to meet for talks later on Tuesday even as Downing Street insisted that a final deal had not yet been struck.
As pressure builds on the prime minister, who is also facing calls to allow MPs a vote on any final deal, the Times newspaper reported that some ministers could be prepared to resign if Sunak’s solution.
A No10 source told PA news agency that central to Mr Sunak’s focus was safeguarding Northern Ireland’s place in the United Kingdom.
There are hopes that a fresh settlement on post-Brexit arrangements in Northern Ireland will be able to secure the return of powersharing at the Stormont Assembly, after the DUP walked out in protest at the protocol last February.
On Monday, foreign secretary James Cleverly and the EU’s Maros Sefcovic agreed to hold a face-to-face meeting in the coming days after a “productive” video discussion.
Sources in Brussels welcomed the move to schedule in-person talks as a positive step, but said a location had not been set.
Focus has also turned to the fate of the Northern Ireland protocol bill, which is currently stalled in the Lords and would allow ministers to override parts of the protocol, after Boris Johnson called on ministers to press on with legislation enabling them to override parts of the protocol.
The intervention by the former prime minister, who negotiated the protocol but whose government also tabled the bill at Westminster after unionist outcry at the deal, was a sign that some backbenchers may try to scupper any agreement brokered by Sunak if it fails to address longstanding gripes about the settlement in Northern Ireland.
Home secretary Suella Braverman on Monday described the bill as “one of the biggest tools that we have in solving the problem on the Irish Sea”.
Braverman, a longstanding Eurosceptic, argued that Sunak is right to be “committed to finding a pragmatic solution to resolve these issues”.