Britain’s controversial plan to deter migrants without papers from landing on British shores was on Tuesday poised to become law, prompting criticism from the United Nations. The legislation would outlaw asylum claims by all arrivals via the Channel and other “illegal” routes, and transfer them to third countries, such as Rwanda. It was proposed in response to years of growing numbers of dangerous cross-Channel journeys from northern France in small boats. Opposition to the bill was finally crushed at a late-night sitting just hours before a barge that will be used to house migrants arrived at a port on England’s south coast. The Bibby Stockholm barge moored in Dorset’s Portland Port is expected to house 500 asylum-seekers later this month. The UN refugee agency condemned the passage of the government’s Illegal Migration Bill as a “breach of international law” and warned it would expose refugees to “grave risks”. “This new legislation significantly erodes the legal framework that has protected so many,” said UN High Commissioner for Refugees Filippo Grandi. It also set a “worrying precedent for dismantling asylum-related obligations that other countries, including in Europe, may be tempted to follow”, added UN human rights chief Volker Turk. Opponents in the unelected upper house had sought to soften the bill by proposing changes. But amendments to parts of the legislation including modern slavery protections and limits on how long child migrants can be detained were voted down in a series of votes. The bill will now become law following the formality of “royal assent” from King Charles III. More than 45,000 migrants arrived on the shores of southeast England on small boats in 2022 — a 60-percent annual increase on a perilous route that has been used by more people every year since 2018. Immigration — both legal and illegal — has long been a key political issue in the UK and was one of the main battlegrounds of the Brexit referendum in 2016, which saw the country leave the European Union. Prime Minister Rishi Sunak, who has vowed to “stop the boats”, has insisted the Rwanda plan would have an important deterrent effect by showing that no-one who arrives illegally in the UK will be allowed to stay. The UN, however, says the 1951 Refugee Convention “explicitly recognises that refugees may be compelled to enter a country of asylum irregularly”. The Conservative government’s Interior Minister in the upper house Simon Murray said the sheer number of arrivals had “overwhelmed” the UK’s asylum system and was costing taxpayers £6 million ($7.8 million) a day in accommodation costs. “If people know there is no way for them to stay in the UK, they won’t risk their lives and pay criminals thousands of pounds to arrive here illegally,” he said. “It is therefore only right that we stop the boats and break the business model of the criminal gangs exploiting vulnerable people,” he added. The Rwanda plan, announced by then-prime minister Boris Johnson last year, was blocked at the last minute by the European Court of Human Rights, which is separate from the EU, and is still mired in legal challenges. The UK government last month said it would appeal a judgement by three Court of Appeal judges who ruled that Rwanda could not be considered a safe third country. Sunak said he respected the court but “fundamentally” disagreed with the judge’s conclusions. To date, no deportation flights to Rwanda have taken place. Rights groups accuse Rwanda — ruled with an iron fist by President Paul Kagame since the end of the 1994 genocide that killed around 800,000 people — of cracking down on free speech and opposition.