LONDON: London's High Court is set to hear further cases brought by asylum seekers appealing against their removal to Rwanda on Tuesday, ahead of the first scheduled flight to the country under Britain's controversial new policy.

As part of an initial 120-million-pound ($148 million) deal with Kigali, Britain will send some migrants who arrived illegally by crossing the Channel in small boats from Europe.

Britain's Conservative government says the deportation strategy will undermine people-smuggling networks and stem the flow of migrants risking their lives in Channel crossings, but the United Nations' refugee chief has described the plan as "catastrophic".

The court on Monday threw out last ditch bids by human rights groups and campaigners to stop the first flight under the policy, due to take off on Tuesday, meaning it can proceed.

But amid legal challenges, only a few people are now scheduled to leave on that first plane.

Initially, some 37 individuals were scheduled to be removed on the first flight, which charities said included people fleeing Afghanistan and Syria as well as Iran and Iraq.

But the charity Care4Calais said that number had fallen to just six, with at least three High Court appeals for individuals scheduled for Tuesday.

Human rights groups say the policy is inhumane and will put migrants at risk. The UNHCR has said Rwanda, whose own human rights record is under scrutiny, does not have the capacity to process the claims, and there is a risk some migrants could be returned to countries from which they had fled.

Prime Minister Boris Johnson, however, has said it is important to break the business model of criminal gangs who run the boats.

A full hearing to determine the legality of the policy as a whole is due in July.