Boris Johnson suggested lawyers representing migrants were “abetting the work of criminal gangs” as last-ditch court hearings took place ahead of the first flight sending asylum seekers to Rwanda.

       The Prime Minister insisted the Government would not be deterred from its policy, despite criticism from the Church of England and reportedly also from the Prince of Wales.

       Mr Johnson acknowledged there had been criticism of the plan from “some slightly unexpected quarters” but highlighted the legal profession as the main source of opposition to the Rwanda policy, which will see asylum seekers sent on a one-way trip to the African nation.

       As Mr Johnson stepped up his attack on the legal profession, Supreme Court president Lord Reed pointedly referred to lawyers “performing their proper function” representing their clients against the Government as he dealt with one of the cases related to the Rwanda policy.

       At a Cabinet meeting on Tuesday, Mr Johnson said: “They are, I’m afraid, undermining everything that we’re trying to do to support safe and legal routes for people to come to the UK and to oppose the illegal and dangerous routes.”

       Recommended Two British fighters sentenced to death by Russian separatists - live

       He said what the “criminal gangs are doing and what … those who effectively are abetting the work of the criminal gangs are doing, is undermining people’s confidence in the safe and legal system, undermining people’s general acceptance of immigration”.

       The Prime Minister was later asked, on a visit to Staffordshire, whether the UK would have to leave the European Convention on Human Rights to avoid the kind of legal battle he faces.

       He said lawyers were “very good at picking up ways of trying to stop the Government from upholding what we think is a sensible law”, adding: “Will it be necessary to change some laws to help us as we go along? It may very well be and all these options are under constant review.”

       Supreme Court president Lord Reed (Kevin Leighton/UK Supreme Court/PA)

       (PA Media)

       The Government already plans a shake-up of human rights laws, with a new Bill of Rights promised in the Queen’s Speech delivered in May.

       With the first flight to Rwanda expected to carry a handful of migrants due to depart on Tuesday, cases involving the potential passengers were heard at the High Court and Supreme Court.

       An application for permission to appeal by an Iraqi man seeking to avoid being sent to Rwanda was rejected by the Supreme Court.

       But Lord Reed said: “In bringing that application, the appellant’s lawyers were performing their proper function of ensuring that their clients are not subjected to unlawful treatment at the hands of the Government.”

       (PA Graphics)

       (PA Graphics)

       A plane believed to be the one which will carry the first asylum seekers to Rwanda was at Boscombe Down military base on Tuesday ahead of its flight.

       Just seven people are due to be on board, following a string of legal challenges and Home Office reviews, but two of those were still seeking a High Court order to prevent them being sent to Rwanda.

       Challenges by two other asylum seekers were rejected earlier on Tuesday.

       Foreign Secretary Liz Truss said the flight to Rwanda will take off no matter how few people are on board.

       She said “some” individuals would be on the plane to Africa on Tuesday evening but could not say how many as she insisted the scheme is both legal and “value for money”, despite the reported ￡500,000 cost of the flight.

       Downing Street said the current approach cost the UK taxpayer ￡1.5 billion every year already, with almost ￡5 million a day accommodating asylum seekers in hotels.

       The archbishops of Canterbury and York, along with the other Anglican bishops in the House of Lords, condemned the “immoral” plan.

       Recommended Rwanda: Boris Johnson says scheme will offer migrants ‘safe legal routes’ to UK British Government does not understand Good Friday Agreement – Taoiseach Andrew is ‘a very good man’, says Duchess of York

       Archbishop of Canterbury Justin Welby said: “Deporting asylum seekers should shame us as a nation.”

       On Monday, three Court of Appeal judges upheld a High Court ruling that the flight to Rwanda could go ahead, rejecting an appeal by two refugee charities and the Public and Commercial Services union.