Two last-ditch legal challenges that attempted to halt the inaugural flight carrying asylum seekers to Rwanda have been rejected by judges. The court of appeal upheld a previous decision to reject an injunction blocking the first flight, which was due to take off for the east African state on Tuesday. Separately, the high court refused to grant a second urgent general injunction application. But Home Office sources have admitted there was a risk that the flight could be cancelled anyway after individual legal challenges meant that fewer than 10 people were expected to board the plane. One charity, Care4Calais, said on Monday afternoon there were fewer than eight. “I think it could be cancelled,” said a government source. “This is due to individual cases rather than a blanket challenge.” A coalition of two refugee charities, Detention Action and Care4Calais, and the PCS union, which represents Border Force staff, were granted leave on Friday to appeal against the rejection of their injunction in the court of appeal on Monday morning. After an urgent hearing at the Royal Courts of Justice, three senior judges dismissed the appeal, saying there was no error in the decision of Mr Justice Swift. A second urgent general injunction application to block flights, from the charity Asylum Aid, was rejected by Swift on Monday. Three other live applications for interim relief are expected to be heard on Tuesday morning. Lawyers acting on behalf of those earmarked for removal are said either to have lodged legal appeals over the weekend or warned they would do so on Monday or Tuesday. Many are doing so under the Human Rights Act or modern slavery legislation. An Iranian human rights whistleblower – who was told last week he would be flown to Rwanda despite fleeing to the UK after giving first-hand testimony of potential violations by the Iranian government – is among those to have received a letter this weekend saying he will not be sent on Tuesday to the east African country. The man, whose plight was first highlighted in the Guardian, received a letter from the Home Office, which was signed off on Sunday, and said the fear of another attempt at deportation remained. “I am still very stressed about what will happen next,” he said. Another Iranian man was still on the list on Monday, it is understood. Conservative MPs cheered in the House of Commons after it emerged that the appeal had failed. The Scottish National party home affairs spokesperson, Stuart McDonald, asking an urgent question, told the Commons: “This is not world-leading policy. If anything, this is leading us to the total shredding of the refugee convention. “This cash-for-deportations policy is akin to state-sponsored trafficking and transportation.” The archbishops of Canterbury and York and the other 23 bishops that make up the entire senior leadership of the Church of England have criticised the “immoral policy”, saying it “shames Britain” in a letter published in the Times on Tuesday. Activists believe that the flight could take off from either Stansted airport or RAF Lyneham. A Spanish airline has reportedly agreed to undertake the deportation flight on behalf of the Home Office. Priti Patel, the home secretary, has maintained that the offshoring policy will help to stop the growing numbers of people crossing the Channel in small boats to find sanctuary in the UK. Questions remain over the status of those who have been threatened with deportation. Before Monday’s court hearings, Boris Johnson defended the Rwanda plan despite the reported criticism from the Prince of Wales, who was quoted at the weekend as describing it as “appalling”. The prime minister insisted the plan was aimed at breaking the business model of people-trafficking gangs. Asked if Charles was wrong, Johnson told LBC Radio: “What I don’t think is we should support is continued activity by criminal gangs.” The environment secretary, George Eustice, on Monday insisted that sending people to Rwanda was “the right thing to do”. Asked on Sky News whether he could confidently say that “more than one person” would be flying on the first flight after reports that far fewer people were due on board than the official figure of 31, he replied: “Lawyers will continue to make these sorts of noises but of course we put in place an agreement with Rwanda.” In an article for the Telegraph, Rwanda’s high commissioner, Johnston Busingye, insisted the country would be a “safe haven”. Busingye said he was “disappointed” that critics had questioned Rwanda’s motives for agreeing to the scheme and doubted its ability to provide a safe haven to vulnerable asylum seekers.