The sacked home secretary Suella Braverman is among the right-wingers pushing to withdraw from the convention after the Supreme Court rejected the plan to put asylum seekers on one-way flights to Rwanda.
But Mr Hunt insisted the government did not want to leave the convention – and claimed that Mr Sunak would “succeed” in getting the flights going and stopping the boats by next year.
“With Rishi Sunak, we have the most persistent and most determined prime minister I have ever worked with,” the chancellor told the BBC’s Sunday with Laura Kuenssberg.
“When it comes to solving fearsomely complex problems, I never worked with anyone as phenomenal as Rishi ... When you interview me next year, we will be having a discussion about how we succeeded in this plan.”
Grilled on whether the government could leave the convention, Mr Hunt said: “We don’t believe at this stage that that is necessary ... We don’t believe it will come to that, at this stage – we don’t want to do that.”
However, the chancellor added that the government was determined to stop “foreign judges” from deciding who comes to the UK. “In the end, our bottom line is clear – it is elected representatives in parliament that should make the decision.”
Mr Sunak’s two-pronged strategy for dealing with the Supreme Court ruling is to announce an emergency law that he says will enable parliament to “unequivocally” declare Rwanda a safe destination for asylum seekers.
The PM will also publish an upgraded agreement with the country, which is expected to attempt to address the court’s concerns around “refoulement” – the potential for refugees rejected by Rwanda to be sent back to the country they are fleeing.
But Ms Braverman and other Tory MPs want to go further, saying that the UK’s domestic and international obligations – the Human Rights Act and the convention – need to be made invalid using “notwithstanding clauses”.
Mr Sunak is said to be weighing up some elements of the hardline plan proposed by Ms Braverman – including a move to make clear that designating Rwanda a safe country would override the Human Rights Act.
One senior Tory MP, a moderate ally of Mr Sunak, told The Independent this was “almost certainly necessary” to avoid further court challenges to the Rwanda flights. Some Tory MPs are pushing Mr Sunak to go further still by coming up with a “derogation” of the convention in the case of Rwanda.
Mr Sunak’s Rwanda plan is “probably dead” in its current form, former Supreme Court judge Lord Sumption told Sky News. He also suggested that judges at the European Court of Human Rights in Strasbourg, which oversees the convention, would ultimately come to a similar view as the UK Supreme Court.
Challenged on whether the government would be able to introduce emergency Rwanda legislation quickly, Mr Hunt told Sky News on Sunday: “I think so – that’s the plan ... We will do it lawfully, and if we need to change the law, we’ll do that.”
Tory ministers are considering whether to give an “effective amnesty” to migrants who have arrived via small boats since July and are facing the prospect of being sent to Rwanda, according to The Sunday Times.
The Home Office is mulling whether they should be allowed to make an asylum claim – having been left in limbo by July’s Illegal Migration Act – as it fears a fresh legal challenge following the Supreme Court’s Rwanda ruling.
Meanwhile, the government is reported to be planning to send Home Office officials to Rwanda, as it attempts to tweak a treaty Britain signed with the central African country.
A government source told The Sunday Telegraph that British civil servants “will be doing training and assisting with case working in Rwanda”. But sources played down the idea that this was anything new, pointing to the fact that the Home Office already has a team in Rwanda.
The new home secretary, James Cleverly, told the newspaper: “We have been working on a new treaty with Rwanda, which will be ratified without delay. It will guarantee in law that those who are relocated from the UK to Rwanda will be protected against removal from Rwanda.”
Mr Sunak is expected to set out a new treaty with Rwanda this week, but the far trickier business of emergency legislation could take several weeks.
It comes as Ms Braverman used an interview with The Mail on Sunday to criticise Mr Sunak after he sacked her in the wake of her accusation of police bias over pro-Palestine rallies and her suggestion that people sleeping rough were making a “lifestyle choice”.
She said the prime minister had been lacking in “moral leadership” over the pro-Palestine marches in the last month, accusing him of making “tepid and timid statements”.
The former cabinet minister also said she has “got a copy” of a pact she alleges she signed with Mr Sunak in exchange for her support for him to become PM last October. But she said she was not intending to release it – yet.
Ms Braverman described her sacking as a “bit odd” and “confusing”, suggesting that Downing Street had approved her now notorious op-ed accusing the police of bias.
“It was a bit odd, because on Wednesday we had agreement with No 10 that I should write an article for The Times. We had put a draft together and exchanged versions with the team at No 10, so I find it all very confusing,” Ms Braverman said.