Lawyers tell the High Court the plan is valid and in the public interest and must go ahead.
Home Office lawyers have said a plan to send asylum seekers to Rwanda must not be stopped by legal challenges – because it is in the public interest.
The government aims to discourage people crossing the English Channel to seek asylum by making it clear many cases will now be dealt with by Rwanda.
In a High Court hearing, the lawyers urged a judge to reject challenges on behalf of individual asylum seekers.
About 100 people have been told they may be on the first flight, on Tuesday.
Just before the start of the hearing, it emerged at least three people have been told they will not now be put on that flight.
The hearing centres on the Home Office’s deal with Rwanda to send some asylum seekers there to have their claims dealt with – if on their way to the UK, they had passed through a safe country where they could have alternatively claimed asylum.
In practice, the policy is targeted at English Channel crossings, with more than 10,000 so far this year.
In papers lodged with the High Court, lawyers said: “Removal to Rwanda pursuant to the migration and economic development partnership [with Rwanda] under the inadmissibility provisions of the immigration rules pursues an important public interest.
“Removals of individuals from the UK in accordance with the MEDP are intended to deter people from making dangerous journeys to the UK to claim asylum, which are facilitated by criminal smugglers, when they have already travelled through safe third countries.
“In particular, but not exclusively, this is aimed at deterring arrivals by small boats.
“It is striking that nowhere in the claimants’ submissions [to stop the flight] is there any consideration of the impact of any public interest factors, still less any analysis or balancing of the importance of the public interest being pursued in this regard.”
The case brought against the Home Office by a coalition of campaigners has two stages.
Firstly, the claimants want to block the removal to Rwanda of specific individuals who have been told they are leaving.
Secondly, they want to challenge the lawfulness of any such transfers to Rwanda.
Raza Hussain QC, representing some of the claimants, told the court that the UN’s refugee agency was concerned about shortcomings in the Rwanda asylum system.
He said the UNHCR’s concerns included evidence that applicants for refuge could be arbitrarily denied proper access to a hearing, a lawyer and an interpreter – and could even find themselves removed to countries that torture.
The UN had not been able to properly monitor the quality of decision-making in the country despite Home Secretary Priti Patel’s claims that Rwanda was safe, he said.
Mr Hussain continued: “These are concerns that have been communicated to the UK authorities and yet the secretary of state’s position is that the UN is giving this plan a green light. That is a false claim.
“This is not the view of a very reputable NGO – it is the view of the UNHCR and it is entitled to very significant weight.”
The lawyer pointed out that the UNHCR has constitutional responsibility for oversight [of international refugee law] and institutional expertise.
“We are not on the ground in Rwanda, the secretary of state is not on the ground in Rwanda,” he said, adding: “The UNHCR is. How could you possibly implement a removal when the UNHCR has said this?”