Tory deputy chairman Lee Anderson has said he will back a series of proposed changes to Rishi Sunak's Rwanda bill in a move that could pave the way for his sacking or resignation.
Mr Anderson, who takes a hardline stance on immigration issues, said he will vote in favour of a series of amendments aimed at toughening up the prime minister's controversial Safety of Rwanda Bill.
A source close to the chief whip said it was not true that Mr Anderson had been given permission to back rebel amendments to the Rwanda Bill.
The bill aims to declare that Rwanda is a safe country while also giving ministers the powers to disregard sections of the Human Rights Act.
However, it does not go as far as allowing them to dismiss the European Convention on Human Rights (ECHR) in a bid to avert challenges to deportations - a demand of some right-wing Tory MPs.
The bill is due to return to the Commons from Tuesday, when debates and votes will be held on the contents of the legislation.
Right-wing Tories, including former immigration minister Robert Jenrick and veteran MP Bill Cash, have tabled a series of amendments designed to firm up the bill.
Mr Jenrick, who resigned in protest at the bill in its current form, has tabled a number of amendments, including one that would block the most "suspensive claims" by migrants against their removal.
Another amendment proposes to make it the "default" that "rule 39" orders from the European Court of Human Rights that have been used to block flights were not binding.
Nearly 60 MPs have signalled that they will back the amendments, which are unlikely to pass because they do not have the support of either the government or Opposition parties.
However, the rebels could decide to vote against the entire bill at third reading, which will take place on Wednesday evening, if Mr Sunak does not amend the bill - although the numbers are predicted to be small.
If the prime minister does amend the bill to please the right, he faces losing the support of the more centrist wing of the party who already feel the bill goes too far in testing the boundaries of international law.
There had been speculation over the weekend that Mr Anderson was planning to back the rebel amendments.
On Monday evening he posted on X: "The Rwanda Bill. I have signed the Cash & Jenrick amendments.
"I will vote for them."
Brendan Clarke-Smith, who is also deputy chair of the Conservative Party, also confirmed he would vote for the rebel amendments, writing on X: "When I was elected in 2019 I promised my constituents we would take back control.
"I want this legislation to be as strong as possible and therefore I will be supporting the Jenrick/Cash amendments. These are arguments I have consistently made and will continue to make."
Asked by Sky News if he knew whether he would be sacked, he replied: "We'll see. It's not for me to decide."
On Monday, Mr Sunak said he was "talking to all my colleagues" as he seeks to dampen the potential for a rebellion over the bill.
He said there are circumstances under which he would also be prepared to ignore injunctions from Strasbourg - so-called Rule 39 orders - blocking flights from taking off to the east African nation.
"I know everyone is frustrated - I'm frustrated about the situation - and they want to see an end to the legal merry-go-round," he told reporters during a visit to Essex.
"I'm confident that the bill we have got is the toughest that anyone has ever seen and it will resolve this issue once and for all."