A plan tailored by the British government to deport asylum-seekers of various nationalities to Rwanda was approved by a UK court on Monday after the appeals court refused to block the plan criticized as inhumane.

Lawyers had been working on behalf of asylum-seekers who were informed they would be deported to Rwanda to prevent London from taking them to a third country, taking the battle to the high court on Monday after they were given the grounds to reject their injunction on Friday.

Immediately after a panel, comprised of three justices of the Court of Appeal in London, declared the decision to give the go-ahead to the plane carrying asylum-seekers, Prime Minister Boris Johnson's office said the first flight would proceed as scheduled on Tuesday.

Had the representatives of the asylum-seekers and the migrant advocacy groups succeeded in court on Monday, the United Kingdom would have had to cancel its plans to deport refugees to Rwanda.

The lawyers and groups had asked the Court of Appeal to overturn a lower court ruling, arguing that the judge had made a mistake when he decided not to issue an injunction last week.

Initial reports showed that London had handed "removal directions" to 130 people who had come to the United Kingdom, but government sources later said the figure was diminishing as lawyers challenged the merits of each deportation order despite there being a major precedent at stake.

Migrant advocacy groups have been denouncing the policy as inhumane and illegal since Johnson announced the plan in April. The announcement of the plan came as Johnson faced the threat of a confidence vote, with some of his lawmakers saying they have lost faith in his leadership as a result of the partygate scandal.

London, however, has dismissed criticism that the policy was inhumane, claiming that it was worse to encourage a system in which many asylum-seekers are exploited by people smugglers.

The Refugee Council revealed that many of the people set to be deported on Tuesday's flight were children, and many of the UK's policies to determine a person's age have been scrutinized. The British Dental Association said it did not recognize the Home Office's technique of using dental checks to determine how old a person is.

Further legal challenges are still underway, however. A similar case filed by lawyers representing a different group of plaintiffs was heard in the High Court on Monday.

Migrants deported under the program would be forced to apply for asylum in Rwanda instead of the United Kingdom. London paid Rwanda 120 million pounds ($158 million) up front and will make additional payments based on the number of people it will be deporting in the future.

One of the lawyers, Raza Husain, argued Monday that the government's plan involved the forced removal of asylum-seekers to a country they did not intend to travel to as part of a policy fabricated with the intention of deterring others from trying to enter the UK.