Rishi Sunak is bracing for a battle with the House of Lords over his controversial Rwanda deportation plan.
The first test will come on Monday with a debate on a motion seeking to delay the Rwanda treaty.
Many peers have already expressed deep unease about the stalled scheme to put some asylum seekers on a one-way flight the east African nation.
But the Prime Minister has urged the Upper House not to block the “will of the people”.
Monday’s debate will centre on a report by the Lords International Agreements Committee recommending Parliament should not ratify the Rwanda treaty until ministers can show the country is safe.
The Government agreed the legally-binding treaty with Kigali in December, saying it addressed concerns raised by the Supreme Court about the possibility of asylum seekers deported to Rwanda then being transferred to a country where they could be at risk.
But the committee said promised safeguards in the agreement are “incomplete” and must be implemented before it can be endorsed.
The debate will give Mr Sunak a first indication of the level of resistance to his flagship policy in the Lords.
The treaty underpins the Government’s Safety of Rwanda (Asylum and Immigration) Bill which compels judges to regard Rwanda as safe.
Downing Street is likely to face attempts by peers to introduce a range of amendments to the proposed legislation.
The Bill is likely to receive its second reading by the end of January, with a third reading possible around the middle of March.
Mr Sunak was warned by a former Tory Cabinet minister to tone down threats to peers.
Nicky Morgan, now a Conservative peer, on Sunday told the BBC: “The last prime minister who used the ‘will of the people’ language, it wasn’t a happy precedent.”
Last week, Mr Sunak endured turbulence in Westminster after a significant cohort of Tory MPs rebelled to back amendments to the Rwanda Bill before largely folding and agreeing to back the plan in a crunch third reading vote.