Two deputy chairs of the Conservative Party have resigned from their roles after they both supported rebel amendments to Rishi Sunak's Rwanda bill.
Lee Anderson and Brendan Clarke-Smith both said they would support proposed changes designed to toughen up Mr Sunak's bill, which seeks to declare Rwanda a safe country to deport asylum seekers to.
Jane Stevenson, a parliamentary private secretary (PPS) in the Department for Business and Trade, resigned from her role after she supported two key rebel amendments.
On Tuesday night, MPs voted on a series of amendments to the Safety of Rwanda Bill, including one submitted by veteran Tory MP Sir Bill Cash, whose amendment sought to disapply international law with regard to Rwanda being a safe country.
In total, 70 MPs backed Sir Bill's amendment.
Sixty Tories, including two tellers who verify the count, supported the amendment, as did two independent MPs who were formerly in the Conservative parliamentary party - Scott Benton and Andrew Bridgen.
They were joined by eight MPs in the Democratic Unionist Party.
However, the amendment was rejected by 529 votes to 68, leaving a majority of 461.
Among the names who backed the amendment were former prime minister Liz Truss, ex-home secretary Suella Braverman, former immigration minister Robert Jenrick and the leaders of the New Conservatives Miriam Cates and Danny Kruger.
MPs also voted on an amendment by Mr Jenrick, which sought to make it more difficult for individuals to make claims against their deportation.
But the Commons again rejected it by 525 votes to 61 votes, among them 59 Tories - including tellers.
The results represent a significant rebellion and potentially spells trouble for the prime minister ahead of the third reading vote on the whole bill on Wednesday, when rebels may vote against it.
Speaking to Sky News's political editor Beth Rigby, Tory MP Mark Francois said the numbers "speak for themselves" and that he hoped the government "will listen and take stock" and possibly tighten the bill.
Mr Kruger, the co-chair of the New Conservatives, told the Politics Hub with Sophy Ridge he was "prepared" to vote against the bill at third reading.
"I really hope that the scale of the vote in favour of the amendments that were debated today will convince the government that they really should adopt these amendments as their own," he said.
However, in an illustration of the dilemma Mr Sunak faces in appeasing the various factions of his party, Damian Green, chair of the One Nation group of moderate Tory MPs, said he would vote against the bill if it was toughened up further as the right-wing rebels demand.
But he said he believed the "high watermark" of the Rwanda rebellion was reached on Tuesday evening.
Mr Sunak had been prepared for a collision with right-wing Tories over the bill, which is aimed at reviving Mr Sunak's plan to send asylum seekers to Rwanda if they attempt to come to the UK via small boat crossings in the Channel.
The bill, which is designed to enable parliament to confirm Rwanda is a "safe country", gives ministers the powers to disregard sections of the Human Rights Act, but does not go as far as allowing them to dismiss the European Convention on Human Rights (ECHR) entirely - a demand of some on the right.
In a joint resignation letter, Mr Anderson and Mr Clarke-Smith said they supported the amendments "not because we are against the legislation, but because like everybody else we want it to work".
"Our support for the party and this government remains as strong as ever and that is why we are so passionate about making this legislation work.
"However, we fully appreciate that with such important roles there is also the issue of being bound by collective responsibility.
"It is with this in mind that we fully appreciate that whilst our main wish is to strengthen the legislation, this means that in order to vote for amendments we will therefore need to offer you our resignations from our roles."
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Liberal Democrat home affairs spokesperson Alistair Carmichael MP said: "Sunak's Rwanda scheme just won't work - and even the deputy chairmen of his own party know it.
"Rishi Sunak has yet again been embarrassed by his own MPs."
A Downing Street source said Mr Sunak accepted the resignations of Mr Anderson and Mr Clarke-Smith and added: "This is the toughest legislation ever brought before parliament to tackle illegal migration.
"This bill will make it clear that if you come here illegally you will not be able to stay. We must pass this bill to deliver what all Conservatives want - a credible plan to stop the boats."