Home Office staff are rebelling against the government’s attempts to tackle small boats crossing the Channel, demanding its recent deal with the French be scrapped because it is “doomed to fail”. A day after France announced it was increasing the number of rescue vessels in the Channel, the Public and Commercial Services union (PCS) has written to the home secretary, Suella Braverman, saying the only solution to the crisis is creating a safe passage visa that allows refugees a secure route to the UK. Rishi Sunak has pledged to make tackling small boat crossings a priority and is expected to issue a statement on the matter this week. However, in a letter to Braverman sent on Saturdayfrom the PCS, which represents 14,000 Home Office and Border Force staff, it said last month’s high-profile £63m deal with the French would fail and should “no longer be pursued”. The letter, from the PCS’s head of bargaining, Paul O’Connor, urged the government to adopt a new approach and that a safe passage visa should be given to refugees so they could avoid making the dangerous crossing at the mercy of organised criminals. It added that the approach to reducing the number of small boat crossings was compounding a sense of misery among Home Office staff, with policies such as the hostile environment making their jobs “deeply unpalatable in a variety of ways”. More than 40,000 people have so far crossed from France on a small boat this year. Another 90, travelling in two boats, made the icy crossing on Friday. Meanwhile, it has emerged that Home Office officials have concluded that plans backed by Braverman calling for a huge crackdown on asylum seekers would not survive a legal challenge. After Braverman’s backing of a report by rightwing thinktank the Centre for Policy Studies – which called for asylum seekers who arrive through irregular routes to be detained indefinitely and banned from settling in the UK – Downing Street is understood to have asked Home Office officials for their view on the legality of such plans. Whitehall sources have revealed that the verdict of Braverman’s own staff was that such plans were vulnerable to legal challenge and would probably be defeated. “No 10 asked Home Office officials for a view on banning asylum for people from white list countries [those deemed safe enough for people to return] and officials told them individual cases will be subject to judicial review, which would be difficult to win, and then the overall policy would likely to be defeated in the courts too,” said the source. The United Nations high commissioner for refugees issued a statement noting concerns over the report’s proposals and what it called a series of “critical factual and legal errors” within it. The likelihood of another legal defeat for the Home Office comes as high court judges prepare to share their view on its contentious plan to send asylum seekers to Rwanda. Despite the plan being announced in April by Braverman’s predecessor, Priti Patel, not a single asylum seeker has been deported to Africa, even though the Home Office has spent tens of millions of pounds on the initiative. The Home Office has been contacted for comment.