The government has suffered a small rebellion in the House of Commons over a deal concerning the Chagos Islands.
It has been urged to “pause” a deal which would hand Mauritius sovereignty of the Islands.
It comes after Donald Trump’s comments on his Truth Social platform which criticised the deal, saying the UK was doing it for “no reason whatsoever”.
The US President’s criticisms come as legislation to finalise the agreement is caught in a wrangle between the Lords and the Commons.
Backbencher Graham Stringer made the request to pause the deal and, alongside fellow Labour MPs Peter Lamb and Bell Ribeiro-Addy, rebelled against the government as they voted in favour of changes to the Diego Garcia Military Base and British Indian Ocean Territory Bill tabled by peers.
The legislation is intended to provide a firm legal basis for the operation of the strategically important Diego Garcia facility.
Ministers have claimed the deal is necessary because international court rulings in favour of Mauritian claims to sovereignty had threatened the future of the base.
As MPs debated the Lords’ amendments to the Bill on Tuesday, Mr Stringer (Blackley and Middleton South) told the Commons: “I have heard (the Foreign Office minister) in this chamber, a number of times, say the United States supported this deal.
“The President of the United States clearly doesn’t support it anymore.”
He added that the United Nations Committee on the Elimination of Racial Discrimination had also asked for the Bill “not to go forward”.
He said: “Does he not think those two things together mean we should pause?”
Mr Stringer later added: “We’re going to pay for something that we didn’t used to have to pay for, it will have consequences for our ability in the Indian Ocean to look after our defence interests, and we don’t know how much it will cost.
“Putting amendments in that will give us an exact figure for those costs is important.”
He argued that the people of the islands – Chagossians – are being “discriminated against”, adding: “The only solution to the central issue of this problem is not a survey that the House of Lords are doing in good faith. It is to have a referendum.”
An amendment proposing a referendum on the sovereignty of the Chagos Islands was ruled out by Speaker Sir Lindsay Hoyle because it would “impose a charge on public revenue”, which the Lords cannot do.
Mr Stringer concluded: “I don’t have the opportunity this afternoon to vote for what I would like to, but I will vote for the amendments that the Lords have put before us.”
Alongside Mr Lamb (Crawley), Mr Stringer voted in support of an amendment which proposed to stop payments to the government of Mauritius “in the event that the use of the base for military purposes became impossible”.
The bid was rejected overall by MPs, who voted 344 to 182, majority 162 to disagree with the amendment.
Mr Stringer and Mr Lamb, in addition to Ms Ribeiro-Addy (Clapham and Brixton Hill) voted in support of an amendment which required the cost of the treaty to be published by the Secretary of State.
This was rejected by MPs voting 347 to 185, majority 162, to disagree with the bid.
Mr Stringer and Mr Lamb also voted in support of a proposal to require the publication of the estimated expenditure of the deal within the first financial year of the Bill becoming law.
This was rejected by the Commons, with MPs voting 347 to 184, majority 163.
Foreign Office minister Stephen Doughty said: “We won’t pause in defending our national security interests and those of our allies.
“We will do the right thing to keep our national security and the operations of this base working as they have done for many decades.”
Intervening, Conservative former minister Simon Hoare argued President Trump had “dropped a depth charge” on his support for the Bill, questioning what the House should read as America’s position.
Mr Doughty said: “The United States and President Trump welcomed this deal in the spring, and when we discuss in detail the reasons why the agreement was needed, the strong protections it includes, and the vital security it provides for Diego Garcia, the administration endorsed the agreement.”
He added: “We will, of course, have discussions with the administration in the coming days to remind them of the strength of this deal, how it secures the base for the United Kingdom and the United States.”