Threatening a new row with the right of his party, the Prime Minister is discussing plans under which Strasbourg will still have the right to consider whether Channel migrants can be sent to Africa.
Senior Tories believe he is preparing to drop the controversial idea of legislating to put illegal migrants outside the jurisdiction of the European Convention on Human Rights.
Mr Sunak has been examining the so-called 'full-fat' plan that would carve out the Rwanda scheme from the ECHR, as advocated by many on the Tory Right.
Prime Minister Rishi Sunak hosts his weekly cabinet meeting with Home Secretary James Cleverly appearing via video link on Tuesday
The PM is set to axe a plan to duck Europe's human rights laws over the Rwanda scheme (Pictured: The European Court of Human Rights in Strasbourg)
Downing Street today said 'no final decisions' had been made on the legislation, which could be published as soon as Thursday.
Migrants could be sent back if crime committed
Migrants who are sent to Rwanda could be returned to the UK if they commit a serious crime, it has emerged.
A spokesman for the Prime Minister said that in 'hypothetical, exceptional circumstances', a deported migrant who is later jailed for at least five years in the central African nation could end up coming back to Britain.
Anyone convicted of a crime would first have to serve their sentence in Rwanda. At that stage, authorities there may decide to revoke their permission to remain. Home Office sources said that migrants may also be able to return here if they win an appeal which had been previously lodged in UK courts against the original decision to remove them to Rwanda.
The spokesman added that there would be a 'high bar' for sending someone back but declined to give examples of circumstances. Last night, a source said the likelihood of a migrant being returned after committing a crime in Rwanda was 'minuscule'.
A source insisted the final legislative package would be 'tough'. But a leading Tory moderate told the Mail No 10 had today given private assurances that plans for setting aside the ECHR had been 'dropped'.
The former Cabinet minister said: 'There are people on the Right of the party shouting that we have to do this and the PM has flirted with it, but it is not necessary. It would not work and it now looks like it is not going to happen, which is a great relief and which makes it more likely we will actually get these flights going.'
Mr Sunak is thought to be leaning towards a 'semi-skimmed' version of the legislation which could override the UK's Human Rights Act but not the ECHR. This could limit legal challenges but leave open a right of appeal to Strasbourg.
A 'skimmed' version of the deal would simply see Parliament declare that, in the light of the new treaty signed with Rwanda today, the African nation is a safe country to send migrants.
Mr Sunak is understood to have been influenced by Foreign Secretary Lord Cameron, who ignored ECHR rulings on prisoner voting for years without leaving it.
The former prime minister told peers today: 'There are occasions when the ECHR makes judgments as they did on the issue of prisoner votes when they said that it was absolutely essential that we legislated to give prisons the vote.
'And I said I didn't think that was the case, I think that should be settled by Houses of Parliament, and the ECHR backed down. So that sort of flexibility may well be necessary in the future.'
A Whitehall source said Mr Sunak was focused on what will work rather than 'crowd pleasing'.
James Cleverly arrived in Kigali on Tuesday to sign a fresh agreement with the Kagame regime to take those arriving in the UK by sea
He visited the Kigali Genocide Memorial during his visit to Rwanda and viewed pictures of the victims of the genocide
'This legislation is going to be tough, but the PM is not interested in doing something that ends up being counter-productive and ties us down in further legal problems,' the source said. 'There is no point having a crowd-pleasing moment if it all falls apart a few months later.'
Supporters of the 'full-fat' plan, who include former Home Secretary Suella Braverman, argue it is the only way to guarantee the scheme is not subject to further debilitating legal challenges and ensure the first deportation flights take off before the next election.
But opponents, said to include senior Cabinet ministers, have warned the plan would damage the country's international standing and put the Government on a collision course with judges who could block a new law, killing off hope of Rwanda flights next year.
Senior figures in the influential One Nation group of Tory MPs tonight warned that leaving the ECHR would be a 'red line'.
Damian Green, who served as Theresa May's deputy, said overriding the ECHR would be 'the wrong thing to do' and make it 'pretty much impossible' to get the legislation through the House of Lords.
Mr Green said the Government should 'think twice' before trying to limit the application of the ECHR or the Human Rights Act. Stephen Hammond, a former One Nation minister, admitted Mr Sunak faced a 'tricky task' but insisted the Rwanda scheme could work without breaching international obligations.
Mr Hammond warned 'mainstream Conservatives may struggle to support a so-called full-fat deal'. Tory whips have warned as many as ten ministers could resign if the Government tries to override the ECHR, including Attorney General Victoria Prentis and Justice Secretary Alex Chalk.
But MPs on the Tory Right signalled they would continue to press for a 'full fat' option. Dozens are said to be ready to back an amendment to the legislation on the ECHR if Mr Sunak drops the plan.
Mark Francois, of the European Research Group of Tory MPs, tonight said the group's lawyers would look for 'unambiguous wording' in the new plan that will ensure deportation flights can take place next year before backing it.