Analysis-Bigger battles await UK's Sunak and his Rwandan migration plan

LONDON (Reuters) - British Prime Minister Rishi Sunak might have emerged victorious from a bruising vote on his flagship Rwanda migration policy, but the bitter divisions that risk turning his party into a "circus" mean any respite is likely to be short lived.

A day of high drama at Westminster on Tuesday culminated in a comfortable win for the government on Sunak's policy of deporting asylum seekers to Rwanda after more than two dozen rebels in the party's right wing abstained in the vote.

That will allow the bill to move to the next stage of the legislative process when lawmakers, including the rebels, will demand changes to a divisive policy that has split Sunak's governing Conservative Party, undermined his authority and put the UK's commitment to international treaties in doubt.

Britain's fifth prime minister in seven years, Sunak has little room for manoeuvre. Toughen the bill to remove a migrant's right to appeal against deportation as demanded by the right and he risks losing centrist lawmakers who are appalled at the prospect of Britain breaching international law.

Leave it as it is and the right wing have said they will vote against it. The rebels may bet that many of the more centrist lawmakers threatening to defeat any effort to toughen up the bill are in government jobs, making it harder for them to vote against the government if it hardens up the bill.

The centrists want Sunak to ignore the rebel demands.

A lawmaker on the party's right-wing said there was no point having a piece of legislation that would not work. But he accepted that the outcome of the Rwanda bill could have further consequences than just UK migration policy.

"The outcome of these negotiations will have a material impact on (Sunak's) security within the party," the lawmaker said.

The sight of different Conservative factions plotting in corners of Westminster as a prime minister's fate hung in the balance brought back memories of the long-running parliamentary battles over Brexit, and underscored how the traumatic departure from the European Union had shattered the once stable nature of British politics.

While Sunak greeted the victory by hugging the man in charge of party management, many lawmakers across his party were raging at those who threaten to kill the bill, and with it quite possibly the government, before an election expected next year.

One member of parliament said his colleagues had turned one of the world's most successful political parties into a "circus" while another dismissed them as an "embarrassment".

DEFINING ISSUE

A former investment banker who only entered politics in 2015, Sunak has made reducing migration numbers a defining issue for his government, particularly the tens of thousands who arrive by inflatable dinghies on the English coast's beaches.

While the 745,000 who arrived via legal routes in 2022 are far higher than the around 45,000 who arrived via small boats that year, they are a visible reminder of the government's failure to control its borders.

A plan to deport to Rwanda those asylum seekers who arrive without permission was first struck by former prime minister Boris Johnson in April 2022. But it has since been bogged down by legal appeals before it was finally rejected as unlawful at the Supreme Court last month.

In response, Sunak struck a new treaty with Rwanda and launched emergency legislation that would remove most, but not all, options for legal appeal. Britain has already paid 240 million pounds ($301 million) to Rwanda before anyone has been sent there.

With headlines dominated by political deadlock Sunak's popularity has hit its worst ever net favourability rating in a YouGov poll, dropping 10 points from late November to -49.

The first lawmaker said right-wing colleagues would meet the minister for illegal migration, and send their lawyers to meet those advising government, to try to improve the bill.

That promise of engagement from the government helped improve the mood after the right-wing lawmakers interpreted Sunak's initial approach as "take it or leave it" - a reflection of the prime minister's sometimes prickly nature towards those who question his judgment.

Keeping the party together may be harder than ever however, as the Conservatives have for months trailed the opposition Labour Party by about 20 points in polls, and as many lawmakers have already said they will quit at the next election, giving them little reason to follow party rules.

With tempers rising, a centrist Conservative lawmaker urged Sunak to hold firm and ignore the increasingly "irrelevant" rebels who abstained after days of threatening to go further.

"The rebels look churlish," he said. "They march to the top of the hill only to look idiotic."

($1 = 0.7982 pounds)

(Writing by Kate Holton, Editing by William Maclean)

By Andrew MacAskill, Elizabeth Piper and Kate Holton