British Prime Minister Rishi Sunak on Thursday launched a fight-back in favour of what he dubbed as “the toughest anti-immigration law ever” amid turmoil within the governing Conservative Party after a bruising Cabinet resignation and open attacks by backbenchers over his government’s controversial policy to deport illegal migrants to Rwanda.

Addressing a hurriedly organised press conference from Downing Street, the 43-year-old British Indian leader referred to his heritage as a “child of immigrants” to highlight how his family used the legal route before becoming “proud” British nationals.

“Illegal immigration undermines not just our border control, it undermines the very sense of fairness that is so central to our national character,” said Sunak.

“We play by the rules, we put in our fair share, we wait our turn. That some people can just cut all of that out, you’ve not just lost control of your borders, you’ve fatally undermined the very fairness and trust on which our system is based,” he said.

Keen to turn the increasingly divisive narrative on immigration in his favour, he stressed that since he took charge last year small boat crossings by illegal migrants were down by a third and that he is confident his version of the new Safety of Rwanda Bill will meet the required legal threshold.

“We have blocked every avenue that anyone has ever used in the past to frustrate their removal. All of those avenues have been shut down. So for the people to say something different, the difference between them and me is an inch, given everything we have closed... But that inch by the way is the difference between the Rwandans participating in this scheme and not,” he said, in a clear challenge to those who opposed the bill.

Sunak is caught in the middle of two strands within his party, one on the extreme right voiced by sacked home secretary Suella Braverman calling for an extreme agenda to override legal challenges and the other more centrist view of the UK not being seen to breach its human rights obligations.

The clash came to a head on Wednesday night when Robert Jenrick, someone seen as a Sunak ally, resigned as his Immigration Minister declaring that his boss’ new bill designed to override a Supreme Court block “does not go far enough”.

"I cannot continue in my position when I have such strong disagreements with the direction of the government's policy on immigration," wrote Jenrick in his resignation letter to Sunak.

In his reply letter, Sunak countered by saying that the new bill would be "the toughest piece of illegal migration legislation ever put forward by a UK government" and that his former Cabinet ally’s opposition to it was "based on a fundamental misunderstanding of the situation".

The resignation came soon after a blistering speech by Jenrick’s former boss in the Home Office, Suella Braverman, who made a statement in the House of Commons to warn that the Tories under Sunak’s leadership faced “electoral oblivion in a matter of months” unless he sped up a crackdown on illegal immigration.

On Thursday morning, she followed this up by calling on the Prime Minister to “change course” before it is too late.

"I urge the PM to change course and change policy… (because) ultimately this bill will fail," she told the BBC.

"He said he would do whatever it takes. I'm telling him there is a way to succeed in stopping the boats and fulfilling that promise. If we do it, if he does it as prime minister, he will be able to lead us into the next election telling the people we have succeeded on this very important pledge," said the Goan-origin minister, who was sacked by Sunak last month as home secretary amid growing policy differences.

The new Rwanda draft bill, to be tabled in Parliament on Thursday and expected to face a vote next week, compels UK judges to treat the African nation as a safe country and gives ministers powers to disregard sections of the Human Rights Act.

It follows the visit by James Cleverly, Secretary of State for the Home Department, to Kigali earlier this week to sign a new treaty with Rwandan Minister for Foreign Affairs Dr Vincent Biruta.

Under the plan, the UK plans to deport illegal migrants to Rwanda while their asylum claims are processed and hopes it will act as a deterrent for people smugglers bringing migrants illegally to UK shores.

Although the bill allows ministers to dis-apply sections of the Human Rights Act, it does not disregard the entire legislation, as some had demanded, and it does not include powers to dismiss the whole of the European Convention on Human Rights (ECHR).

"You can't tweak this problem. We can't do half-measures. We have to exclude international law – the Refugee Convention, other broader avenues of legal challenge," claims Braverman, a former barrister.

The latest row comes as Sunak continues to try and finetune his pitch for a general election expected in the next 12 months, amid a deeply divided Conservative Party which has seen prime ministers come and go in recent years due to infighting.

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