Rishi Sunak has been urged not to drop potential powers to unilaterally override the Northern Ireland protocol, as the first sign of cabinet tensions emerged over the prime minister’s proposed deal with the EU. The call from Suella Braverman not to abandon the bill echoes the same message from Boris Johnson. Sources close to the former prime minister over the weekend urged Sunak to keep the legislation as leverage. The home secretary’s intervention came as Downing Street insiders played down hopes of a deal being struck by Tuesday, despite heightened expectations prompted by Sunak’s discussions with the Northern Ireland political parties last week. Senior Conservatives have questioned whether any deal that does not have the backing of the Democratic Unionist party would secure its ultimate objective, but government sources have stressed that the DUP will not be shown the text of the agreement before it is struck or granted a veto on the contents. There were reports on Monday night that some ministers could even consider resigning over the latest Brexit deal if they felt it undermined Northern Ireland’s place in the UK. The foreign secretary, James Cleverly, who held talks by video link with Maroš Šefčovič on Monday, said “intensive work” continued between the two sides and he would hold a further meeting with the Brussels official later this week, again underlining that a deal was not imminent. Braverman, a former chair of the European Research Group (ERG) of hard Brexiters in the Conservatives, struck a note of caution about plans to drop the bill, understood to be part of the deal package. One senior member of the ERG said her intervention was “heartening”. Stressing the importance of the bill, she told the BBC: “We’ve been aware for some time now of challenges relating to trade, customs and sovereignty when it comes to Northern Ireland and the NI protocol. “The legislation that the government introduced is one of the biggest tools we have in solving the problem on the Irish Sea. It’s clear and it’s right that the PM is committed to finding a pragmatic solution to resolve these issues which are affecting the people of Northern Ireland, and that we find a solution that’s pragmatic and workable both for the EU and the UK.” Downing Street insiders said Sunak would continue conversations with the ERG and the DUP but hope they will be able to move quickly once the final negotiations have concluded. Sunak has been meeting restive MPs in the Commons throughout Monday and Cleverly is expected to address the backbench 1922 Committee this week. The northern Ireland minister Steve Baker attended an ERG meeting on Monday. Sources say there was “a lot of fear of a sell out” but that there was also discussion of the damage a potential reopening of divisions would do to the future of the Tory party at the polls. There is mounting concern that the longer the two sides leave it to strike a deal, the greater the risk of unravelling, with the knottier issues often left to the end of such negotiations. Once a deal is agreed on the Northern Ireland protocol, the government is expected to announce it swiftly, with hopes that the European Commission president, Ursula von der Leyen, could come to London to shake on it. Ministers still hope to put the deal to a vote in the House of Commons, as it would bind in MPs politically, but No 10 has so far refused to commit to a vote. The DUP MP Sammy Wilson reiterated his party’s pledge that Sunak agreeing a deal with the EU without the consent of the party would mean a continued boycott of Northern Ireland’s devolved assembly. Asked if he expected a consensus to emerge this week, Wilson told Sky News: “No, I don’t.” There were, he said, “barriers and hills to climb” for Sunak. The government had “gone into these negotiations with an attitude of defeat, almost”, Wilson added. Senior Conservatives, including those supportive of Sunak, suggested there was little point in progressing without the support of the unionists. “The purpose of the negotiations was to get a deal that would allow DUP to go back into government in Stormont,” one former cabinet minister said. “So DUP support for a deal is the key. Without DUP support, it is pointless.” David Jones, the deputy chair of the ERG, said: “The problem is that DUP has told No 10 that whatever they agree needs to meet the ‘seven tests’. “One of those is that the people of Northern Ireland have to have a say in the laws that govern them, but it is hard to see how they do that without an entirely new agreement. What they are talking about now is some sort of new interpretation of the existing agreement, not a completely new one.” Jones said he understood the DUP had asked to see the text of the full agreement – rather than the political framework – in order to move forward. That request is unlikely to be accepted. Braverman’s intervention on the protocol bill took a similar tone to that of Johnson, as well as other former Brexit-backing cabinet ministers such as Simon Clarke and Jacob Rees-Mogg. Johnson warned at the weekend it would be a “great mistake” to ditch the bill rather than retain it as a backup option. The protocol bill, the brainchild of Liz Truss when she was foreign secretary, would allow the UK to unilaterally override parts of the Brexit treaty, and discarding the bill is seen as a gesture of goodwill when agreement is reached on application of the protocol. The bill is awaiting report stage in the House of Lords, but its progress has been frozen. Senior sources have also indicated there are now doubts about whether the bill is legally sound because of progress on the negotiations. Clarke said it was vital to retain the bill as an option for the government. “We need to make sure that if a deal is struck here, this is genuinely a better one than that which we can achieve through our own legislation to fix the protocol,” he said. “And I think that is quite a high bar because it is going to involve the EU accepting that Northern Ireland cannot be subjected either to EU law or in the single market and that would be a big move on their part.”