Suella Braverman has joined a backlash from rightwing Conservative MPs who are pushing for emergency legislation to overrule the supreme court’s decision on the UK government’s Rwanda deportation plan. A day after accusing Rishi Sunak of “betrayal” after her sacking as home secretary, she called on the prime minister to “legislate or admit defeat”, in a fresh intervention shortly before he promised legislation to stop the plan from being blocked. Braverman said a bill must “block off” UK international and domestic legal commitments, including the European convention on human rights (ECHR) and the Human Rights Act, that have frustrated the Rwanda deportation plans. “This will give parliament a clear choice: control illegal migration or explain to the British people why they should accept ever greater numbers of illegal arrivals settling here,” she said on the social media platform X. “Those who, like me, believe that effective immigration control is vital must understand that they cannot have their cake and eat it: there is no chance of curbing illegal migration within the current legal framework. We must legislate or admit defeat.” Her latest broadside came as at least six MPs were poised to submit letters of no confidence in Sunak, according to Andrea Jenkyns, a rebel backbencher who has already submitted her own. There was a cautious early reaction to Sunak’s pledge from at least one grouping of Conservative MPs on the right, but they warned that his promised legislation must come to parliament within weeks and ensure that flights to Rwanda are in the air within months. The New Conservatives – a grouping of predominantly “red wall” MPs co-chaired by Miriam Cates and Danny Kruger – said that it would need more than a declaration that Rwanda was a safe country, adding: “We must move now to ensure that this time, finally, there is simply no opportunity for rights-based claims against deportation. “The Bill must disapply the Human Rights Act and give effect to the policy notwithstanding the ECHR and Refugee Convention. It must restate the power of Govt to disregard interim rulings from Strasbourg,” they added in a post on X. “We have no time left. This Bill – which must come to Parliament within weeks – must have everything in it to ensure that flights are in the air within months.” Earlier, the former minister Simon Clarke warned of a new “confidence issue” in the prime minister’s judgment and his role as leader of the Conservatives, and said the supreme court ruling had “thrown down a gauntlet”. “I think we are going to have to pass emergency legislation at a minimum to set out that the will of parliament will apply notwithstanding the ECHR and associated conventions that the justices reference,” Clarke told Sky News after the ruling, in which supreme court judges deemed the Rwanda plan unlawful under a range of UK international commitments. After a meeting in parliament attended by MPs such as Iain Duncan Smith and the veteran Eurosceptic Bill Cash, Lee Anderson, the Conservative party deputy chair, told reporters that the government should ignore the law. He said it should “just put the planes in the air” and deport asylum seekers, adding: “I think we should … send them back on the same day.” Asked later if the prime minister was comfortable with Anderson’s call to break the law, Sunak’s spokesperson said: “We appreciate that our MPs have strong views on this because, frankly, the country cares about this.” However, unease in other sections of the party was reflected when the former minister Damian Green later pressed the home secretary, James Cleverly, on the need for the government to “obey the law”. “Does he also agree that those looking at the judgment and thinking that there is simply one lever to pull are going to be disappointed?” Green asked. At least 25 rightwing MPs were said to have attended a meeting earlier, including Cates and Marco Longhi. Jonathan Gullis, a “red wall” MP who was also at the meeting, said they had discussed the need for a plan B, which could involve an Australian-style move to push back boats in the Channel – and even begin dropping people back on French beaches. Kruger said the scope of the ruling meant the UK’s involvement in other treaties and conventions also needed to be considered. “The government should immediately announce an intention to do what is necessary to insist on our sovereignty. That means legislation to override the effect of the European court, of the ECHR itself and of other conventions, including the refugee convention if necessary.” He added: “This feels absolutely existential for our party … if this government will not step up to do whatever it takes to do what the prime minister has promised he will, there is no reason for the public to trust us again.”