Court of Appeal judges are due to rule on whether to block the first flight in the Government’s controversial plan to send some asylum seekers to Rwanda after Boris Johnson defended the policy.

The Prime Minister has said the Government had anticipated “a lot of teething problems” with the policy, but said the move is necessary to stop illegal people-smuggling rackets on either side of the Channel.

The Public and Commercial Services union (PCS), which represents more than 80% of Border Force staff, and charities Care4Calais and Detention Action have gone to the Court of Appeal after the High Court’s ruling on Friday that the first flight to the east African country can go ahead.

Lawyers for the three groups and one person due to be removed are asking for an interim block on removing the now-11 people due on Tuesday’s flight until the full hearing of whether the policy is lawful next month.

Raza Husain QC told the court: “The justice of the situation indicates that a general order should be made.”

The barrister said the policy featured “a serious interference with basic dignity” and that the High Court judge had wrongly assessed the strength of their claim.

He said in written submissions: “The policy presently involves executive detention, forcible removal from the jurisdiction, transportation to a country from which they have not sought protection and to which they do not wish to go, in circumstances where the individuals concerned are exercising a legal right; and their removal is intended to deter others.

“This amounts, on any view, to a serious interference with basic dignity… where those individuals have already suffered significant trauma and have mental health issues.”

Mr Husain argued that the High Court judge who refused to block the flight on Friday, Mr Justice Swift, had wrongly decided the “balance of convenience”.

He said in written submissions: “If interim relief is refused and the claim succeeds, each claimant will be entitled to a ‘bring back’ order.

“If it is possible to bring the individuals back, which it may not be, this will have very significant administrative cost.

“Every individual who has been forcibly removed is also likely to have significant claims for damages… This potential cost to the taxpayer, in itself outweighs any inconvenience of a six-week delay pending removal pending trial.”

The Home Office has defended the policy.

Rory Dunlop QC, for the department, said: “The flight tomorrow is important.

“This is a policy which is intended to deter dangerous and unnecessary journeys, journeys from safe third countries by people who do not need to make that journey to be safe, they can claim in France or wherever it is.

“This is a policy that if it works, could save lives as well as disrupting the model of traffickers.

“Even if we are just talking about cancelling a flight tomorrow, there is prejudice to the public interest, to the enactment of decisions that may have that deterrent effect.”

The High Court heard the UN refugee agency, the UNHCR, has multiple concerns about the system in Rwanda, including discriminatory access to asylum, a lack of legal representation and other “deep-rooted structural problems”.

On Monday, Mr Dunlop said: “The Secretary of State has listened and seriously considered the concerns raised by the UNHCR and has deliberately negotiated arrangements to provide assurances in relation to those concerns.”

Lord Justice Singh, Lady Justice Simler and Lord Justice Stuart-Smith are due to give their decision on the appeal on Monday afternoon.

A second case is also due to be heard in the High Court on Monday afternoon after Asylum Aid, a refugee charity, applied for an urgent interim injunction to stop the Government flying migrants to Rwanda.

Ahead of both hearings on Monday, Mr Johnson told broadcasters during a visit to a farm in Cornwall: “I always said that it will begin with a lot of teething problems and you will have a lot of legal action against it and they will try and delay it – that’s inevitable.

“But what we’re trying to do is stop the business model of criminal gangs who are preying on people moving them across the Channel in unseaworthy vessels, risking their lives and sometimes costing their lives.”

It came as Rwandan high commissioner Johnston Busingye told The Telegraph that his country will be a “safe haven” for migrants, after The Times and the Daily Mail reported that the Prince of Wales allegedly said in private that the policy is “appalling”.

Mr Johnson declined to comment on whether Charles was wrong in his comments, adding: “This is about making sure that we break the business model of criminal gangs who are not only risking people’s lives but undermining public confidence in legal migration.”

The Prime Minister’s official spokesman later said Mr Johnson “has nothing but respect and admiration for the Prince of Wales, who’s spoken out on a number of issues, not least the environment”.