Justin Welby said the Illegal Migration Bill represented a “dramatic departure” from Britain’s obligations under the 1951 Refugee Convention to allow arrivals to make asylum claims.
“I urge the government to reconsider much of the bill – which fails to live up to our history, our moral responsibility and our political and international interests,” said the Church of England’s most senior bishop.
The archbishop said home secretary Suella Braverman’s bill “fails utterly” to deal with the long-term challenge of people trafficking, undermines international cooperation and damages the UK’s global repuation.
“We need a bill to stop the boats. We need a bill to destroy the evil tribe of traffickers – the tragedy is that without much change this is not that bill,” he told the Lords on Wednesday.
Mr Welby added: “It is isolationist, it is morally unacceptable and politically impractical to let the poorest countries deal with the [refugee] crisis alone.”
The international protections for refugees are “not inconvenient obstructions to get round by any legislative means necessary”, the archbishop also told parliament.
He said: “Even if this bill succeeded in temporarily stopping the boats – and I don’t think it will – it won’t stop conflict or climate migration.”
Calling on the government to put new “safe and legal routes” for refugees in place, he warned: “We cannot wait for the years before that happens.”
The archbishop also followed Labour in criticising the lack of new government measures to tackle “evil” people-smuggling gangs – arguing that the bill failed to “engage with criminal traffickers directly and offensively”.
Responding the Mr Welby’s criticism, Mr Sunak’s official spokesperson insisted that the plan to detain and deport Channel migrants was the “compassionate and fair thing to do”. The No 10 spokesperson also said Mr Sunak believed “there is nothing compassionate” about allowing people to die in the English Channel.
Immigration minister Robert Jenrick has accused Mr Welby of being “wrong on both counts” when asked about his comments calling the bill “morally unacceptable and politically impractical”.
Mr Jenrick told the BBC’s World At One “there’s nothing moral about allowing the pernicious trade of people smugglers to continue”.
Earlier, Ms Braverman warned peers not to stand in the way of the “will of the British people” by blocking the plan to swiftly remove small boat migrants either to their home country or a third country such as Rwanda.
As the controversial legislation returned to the Lords on Wednesday, a group of 174 campaign groups and charities signed an open letter calling for the government to ditch the bill – saying it was “effectively a ban on asylum”.
The bill would limit the ability of the European Court of Human Rights (ECHR) to prevent deportation. Critics argue the reforms will break international law, and former Tory leaders Theresa May and Iain Duncan Smith have warned it also threatens Britain’s existing modern slavery protections.
Lib Dem peer Lord Paddick proposed a so-called fatal motion at stopping it in its tracks but it was dismissed by Labour – who warned it could backfire and deny the peers the chance to amend the bill.
Lord Paddick argued the legislation was “a low point in the history of this government”, while Labour frontbencher Lord Coaker said the Tories were “playing fast and loose with our place in the world and our respect for international law”.
Labour’s Lord Dubs – a child refugee who fled the Nazis before the Second World War – said failing to uphold the international laws would mean “notorious abusers of human rights will simply say, ‘Well, if the United Kingdom doesn’t do it, why should we?’”
Speaking for the government, Home Office minister Lord Murray faced jeers and shouts of “shame” in the Lords as he argued it was a “compassionate response” to the small boats problem.
Former Tory leader Lord Howard backed the bill, arguing that the ECHR ruling which halted the first planned flight to Rwanda last year was “contrary to all the rules of natural justice”.
Meanwhile, the Bibby Stockholm barge arrived in the UK on Tuesday. It is set to be docked in Portland, Dorset, and house 500 asylum seekers. Some on social media compared it to a “prison hulk”, while the Green party called the offshore plan “cruel, insensible and immoral”.
Portland Town Council leader Jim Draper told Sky News on Wednesday that he had been told by the government that migrants would be “free to come and go” in the coastal town. But he warned that the “mechanics” were unclear and no funding had been provided.
Mr Draper said: “They’re talking about a bus that will take 30 people at a time on an hourly service going in and out, so it’s not going to allow many in and out.”
It comes as the plan to clear the asylum backlog by fast-tracking applications from five wartorn countries is in a “complete mess,” a government source told The Times.
Only 10 per cent of the forms offered to asylum seekers from countries including Afghanistan and Syria are said to have been filled-in properly which mean a lengthier process of interviews have had to take place.