By Michael Holden and Sam Tobin
LONDON (Reuters) - British Prime Minister Rishi Sunak will learn on Wednesday whether his government can finally go ahead with its plan to deport asylum seekers to Rwanda when the UK Supreme Court gives its verdict on the scheme's lawfulness.
Sunak is seeking to overturn a ruling in June that found the plan to send migrants who arrived in Britain without permission to the East African nation was unlawful as Rwanda was not a safe third country.
Five judges from the Supreme Court will deliver their ruling at about 1000 GMT.
The Rwanda scheme is the central plank of Sunak's immigration policy as he prepares to face an election next year, amid concern among some voters about the numbers of asylum seekers arriving in small boats on Britain's shores.
This year more than 27,000 people have arrived on the southern English coast without permission, after a record 45,755 were detected in 2022.
Originally launched by one of his predecessors, Boris Johnson, Sunak argues the plan would deter migrants from making the often perilous journey across the Channel from Europe and thus smash the business model of people traffickers.
Critics, who range from opposition lawmakers as well as some in his own Conservative Party to church leaders and the United Nations refugee agency, say the policy is flawed, immoral and simply will not work. Even King Charles is reported by media to have voiced concern.
Victory in the court would allow Sunak, whose Conservatives are trailing by about 20 points in opinion polls, the chance to say he is making progress with his plan to "stop the boats", one of the five key pledges of his premiership.
The ruling has taken on even greater political significance in coming days after he sacked Home Secretary Suella Braverman, a popular figure on his party's right-wing whose remit included dealing with immigration.
She had said it was her "obsession" to see Rwandan deportation flights, and is likely to lead calls from Conservatives lawmakers for Britain to pull out of the European Convention on Human Rights (ECHR) if the court says the scheme is unlawful.
Asked if the government had an alternative plan, a spokesperson for Sunak said on Tuesday: "We have options for various scenarios as you would expect", but that leaving the ECHR was not discussed by cabinet.
(Reporting by Michael Holden; Editing by Alex Richardson)