The first asylum seekers to be deported from Britain to Rwanda will come from a group of 5,700 people that Kigali has agreed in principle to take, according to a British government document published on Monday.

Under a scheme that has divided political opinion in Britain, anyone who has arrived illegally after Jan. 1, 2022 is eligible to be deported to Rwanda. More than 50,000 people have arrived since that date, official figures show.

Last week, Britain passed legislation that aims to override a UK Supreme Court ruling that the policy was unlawful by declaring that Rwanda must be treated as safe by judges and officials. British Prime Minister Rishi Sunak said he expected the first flights to take off in 10 to 12 weeks.

In the document that assesses the impact of the Migration and Economic Development Partnership with Rwanda, agreed between Britain and Rwanda, the Home Office (interior ministry) said the government had retained a cohort of people who had been told their asylum claims were inadmissible, and could be removed to Rwanda once the new law came into force.

“Of the 5,700 people Rwanda has in principle agreed to accept, 2,143 continue to report to the Home Office and can be located for detention,” the document said.

Sunak believes his plan will stop people making the dangerous trip across the Channel from France by smashing the model of people smugglers, but critics say the policy is inhumane, and further court challenges are likely.

Last week, five migrants including a child, died attempting the crossing, while more than 7,000 have made the journey so far this year – the first time that figure had been reached by the end of April.

The Irish government has said the threat of being sent to Rwanda was causing migrants to head to Ireland from Britain, which London said showed the Rwandan scheme would work.

“The UK’s new deterrent is clearly working and having some impact already, an impact that will obviously increase as the first flights depart for Rwanda,” Britain’s Northern Ireland minister Chris Heaton-Harris said on Monday.

“Now the Rwanda Act has become law, we will begin the process of removing those identified for the first flight.”