The leader of the world's Anglicans on Monday warned that the UK government's plan to send migrants to Rwanda was leading the nation down a "damaging path", as he waded into the highly charged political issue.
Archbishop of Canterbury Justin Welby said the controversial plan of Prime Minister Rishi Sunak's Conservative government would "outsource our legal and moral responsibilities for refugees and asylum seekers".
He made the comments during a debate in parliament's unelected upper chamber the House of Lords, which is scrutinising the government's Safety of Rwanda (Asylum and Immigration) Bill.
"With this bill, the government is continuing to seek good objectives in the wrong way, leading the nation down a damaging path," said Welby, who is the highest-ranking cleric in the Church of England, the mother church of global Anglicanism.
The legislation aims to combat irregular immigration by deporting asylum seekers to the east African country.
Sunak has put the plan at the centre of his pledge to "stop the boats" of migrants crossing the Channel from northern France in flimsy and ill-suited vessels.
The bill is his answer to a UK Supreme Court ruling late last year that deporting asylum seekers to Kigali is illegal under international law.
If passed, the legislation would compel judges to treat Rwanda as a safe third country.
It would also give UK ministers powers to disregard sections of international and British human rights legislation.
Welby, one of 26 senior Church of England bishops and archbishops who sit as the Lords Spiritual in the House of Lords, said the bill was damaging for asylum seekers in need of protection and safe legal routes.
He added that it was also damaging for Britain's "reputation" in relation to international law.
"Worst of all, it is damaging for our nation's unity in a time when the greatest issues of war, peace, defence and security need us to be united," the archbishop said.
Welby said the legislation offers "only ad hoc one-off approaches" and that Britain "can as a nation do better than this bill".
He warned that Britain might face 10 times the number of migrants in the coming decades and called for a "wider strategy" for refugee policy, involving international co-operation.
"This bill continues, wherever it does it, to outsource our legal and moral responsibilities for refugees and asylum seekers, with other countries far poorer already supporting multitudes more than we are now and to cut back on our aid," Welby added.
Sunak, who faces a general election later this year that he is widely predicted to lose, has urged the House of Lords to pass the plan.
He claimed it was the "will of the people" after the legislation cleared the elected House of Commons earlier this month.
But peers, which include former senior judges, have expressed deep unease, particularly about the scheme's calls to ignore international human rights and refugee law.
Welby said that "pick-and-choose approach" to international law "undermines" the UK's standing in the world.
The legislation is expected to pass the second reading stage on Monday but peers may vote for amendments at the crucial third reading later.
Last week, the Lords voted to delay ratification of a related treaty with Rwanda.
