Rishi Sunak’s signature plan to deport asylum-seekers survived a key vote in Parliament, but not before the British prime minister suffered a series of blows to his authority that damaged his hopes of avoiding defeat at a general election later this year.

The House of Commons voted 320 to 276 on Wednesday (Jan 17) in favour of Sunak’s plan to send migrants to Rwanda, after most Conservative Party rebels who had tried to force the government to toughen the Bill fell into line in the final tally. Only 11 Tory MPs ultimately refused to back down and voted against Sunak.

The legislation now advances to the House of Lords, where it is expected to face stiff opposition because the Tories don’t have a majority in the upper chamber.

Sunak challenged the House of Lords not to “frustrate” his flagship bill, warning that the policy is an “urgent national priority.”

“There is now only one question. Will the opposition in the appointed House of Lords try and frustrate the will of the people, as expressed by the elected house, or will they get on board and do the right thing?” Sunak said on Thursday in a press conference in Downing Street. “It’s now time for the Lords to past this bill.”

While Sunak’s office will be relieved to see the legislation clear the Commons and put off any immediate threats to his premiership, the last 48 hours or so have come at a significant political cost. During debates, senior figures in his party have aired their doubts about a central pillar of his strategy months before he faces voters.

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Even some Tories who voted with the government expressed their reservations, including former Cabinet minister Jacob Rees-Mogg, who said Sunak faces a challenge in getting deportation flights started before going to the polls.

“The real problem for this bill is that we’ve got eight or nine months until an election, and that this bill will probably take longer than that with all the legal ramifications,” he told Sky News after the vote. “This bill in and of itself is a perfectly reasonable bill, it could just have been better.”

Much of the damage was done on Tuesday when Lee Anderson – who Sunak made deputy party chairman to try to stop the Tory party from haemorrhaging support to more right-wing parties – dramatically resigned to vote against the government. The decision, though not accompanied by a broadside against Sunak, signalled to the prime minister’s critics on the right of the party that Anderson didn’t believe the Rwanda bill is tough enough to work.

Still, Wednesday’s majority of 44 was the same as in December’s contentious vote at the preliminary stage in the House of Commons, indicating that the battle lines haven’t substantially changed.

Sunak agrees with right-wing Conservative MPs that a crackdown on asylum-seekers is critical to reversing a 20-point poll deficit to the opposition Labour Party and to prevent Nigel Farage’s Reform UK from gaining ground. Many Tories say the small boats carrying migrants to Britain is what voters in their district complain about most, although polls show the issue trails broader worries about the cost-of-living crisis and the state of the economy.

Sunak made stopping the migrant boats one of the key promises he wants votes to judge him by. His plan is to refuse asylum claims from people arriving by boat and to deport as many as possible to Rwanda. The government says that will serve as a deterrent and reduce the number of crossings.

But that is as far as Tory unity goes, and a group of rebels wanted Sunak to use the Rwanda legislation to legally bar all access to the British courts for asylum-seekers and to dis-apply international human rights law to the UK’s immigration policy. About 60 Conservative MPs voted to change Sunak’s bill along those lines on Tuesday, and roughly the same again on Wednesday.

They included former Home Secretary Suella Braverman and ex-immigration minister Robert Jenrick, who both left Sunak’s government last year after disagreements over the Rwanda plan. Their decisions were widely perceived as an attempt to position themselves for a leadership contest many assume will happen if the Tories lose the general election as expected.

The pair have also been at the forefront of turning the immigration row into something akin to the years of wrangling over Brexit. Just as right-wing Tories tried to push then leader Theresa May into ever more extreme positions, so Braverman and others have tried to turn a willingness to ignore international human rights law on immigration into an issue of ideological purity.

But Sunak said that conceding to the rebels and breaching international law would lose Rwanda’s cooperation. It would have also alienated more moderate Tories, without whom he couldn’t get his legislation through the Commons.

Speaking in Davos, Switzerland ahead of the vote, Rwandan President Paul Kagame signalled his own frustration with the saga, telling reporters the political and legal challenge facing Sunak in getting the deportation programme up and running was “the UK’s problem, not Rwanda’s problem.”

Ultimately, faced with the choice of a bill they don’t love or no bill at all – and the risk of triggering more Tory turmoil that would likely turn off voters – enough rebel MPs opted to back Sunak’s legislation rather than vote it down. “It’s this bill, or no bill,” Conservative MP Bob Seely had warned the rebels. BLOOMBERG