The government insists the proposed legislation - aimed at deterring asylum seekers from crossing the Channel in small boats - is the toughest immigration law in history and will revive the scheme after the UK's Supreme Court ruled it unlawful late last year.

But some Conservative MPs on the right of the party claim it does not go far enough, pushing for harder measures to limit appeals from asylum seekers and to block any rulings from international courts.

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'Unity of purpose' in Tory party, claims minister

Last night, two deputy chairmen of the Tory party and one ministerial aide quit their posts in order to back rebel amendments put forward by veteran MP Sir Bill Cash and former immigration minister Robert Jenrick.

While the amendments were rejected overall by MPs, 60 Conservatives voted in defiance of the government - with further backbench proposals being tabled today.

An overall vote on the bill is also scheduled for this evening, and if around 30 Conservatives vote against it, the legislation could fall.

Rishi Sunak will also face the added pressure of his weekly grilling at Prime Minister's Questions before the debate even begins.

Former minister Jonathan Gullis joined Mr Jenrick and others in saying he was "prepared" to vote down the Rwanda bill if it remained unamended.

But he told Sky News he hoped to "get into 10 Downing Street today" to "talk it out and find a way forward so we can avoid colleagues choosing to either abstain or go in the opposite lobby".

Mr Gullis added: "We firmly believe that the prime minister should see the overwhelming support on his backbenches for wanting to toughen this legislation.

"I hope we can get into 10 Downing Street, we can negotiate this, and then we can come to a place where we can tell all colleagues it's time to go through the aye lobby."

Asked if they were going to invite the rebels in for talks, a Number 10 source said they wouldn't comment on private conversations, but "engagement is continuing".

Illegal immigration minister Michael Tomlinson told Sky News he would be "listening respectfully to colleagues" and he "completely understands" their concerns.

He insisted all the MPs in his party had a "unity of purpose" and were "determined" for the Rwanda bill to be a success, adding this morning: "If you listened and heard and saw what [the rebels] said, they are determined that this policy works.

"They support the prime minister in his aim to stop the boats. He is the one who has the plan to stop the boats."

The minister continued: "We will see more robust debate in the chamber of the House of Commons this afternoon.

"But I know how my colleagues feel... their concerns are my concerns. And I'm determined that we can get this legislation through, that we can stop the boats, because we have a plan to do that."

Speaking to reporters, Chancellor Jeremy Hunt also tried to calm the mood, saying: "We are united in the Conservative Party in our belief we need to solve this problem [of Channel crossings].

"Of course, we have lively debates inside the party about how to deliver the Rwanda policy.

"But the big picture is there's only one major party in British politics that wants to make Rwanda work. That's the Conservative Party."

However, Labour's shadow culture secretary, Thangam Debbonaire, said the internal Tory row showed the "incredibly weak leadership" of Mr Sunak, who couldn't get his MPs to vote as one last night.

"His plan keeps stumbling," she told Sky News. "It literally seems to be his only policy at the moment.

"But he isn't stopping the boats. Nearly 30,000 people came over on small boats last year. He pledged that it would stop in 2023. That's not stopping it."

Asked if there would definitely be a vote on the overall bill amid rumours Number 10 could pull it rather than face defeat, Mr Tomlinson focused on procedure - explaining how the parliamentary timetable would allow the vote if the bill remained unamended.

There has also been no hint that Mr Sunak is willing to concede to the rebel demands as of yet, as not only does the government believe it would risk Rwanda pulling out of the scheme, but Conservatives from the more centrist wing of the party have threatened their own rebellion if the law goes too far.