Sir Keir Starmer faces embarrassment after being compelled to abruptly pause the progression of a law enabling the transfer of the Chagos Islands.

The Prime Minister postponed Parliament’s approval of an agreement to cede the Indian Ocean territory to Mauritius due to a potential defeat looming in the House of Lords.

This decision followed the Conservatives’ proposal of an amendment that called for a 30-day consultation with the Chagossian community.

The Tories accused Sir Keir of avoiding scrutiny over what they termed his ‘surrender’ of the Chagos Islands, intensifying demands for Labour to abandon the deal entirely.

The Diego Garcia Military Base and British Indian Ocean Territory Bill aims to implement the Prime Minister’s agreement to transfer sovereignty of the Chagos Islands to Mauritius.

As per the treaty signed in May, the UK will lease back the strategically crucial joint UK-US military base on Diego Garcia, the largest island in the Indian Ocean region.

Sir Keir has claimed the ‘net cost’ of the agreement to British taxpayers will be £3.4billion, after adjusting for factors including inflation.

But critics have said the true cost is closer to £30billion. They have also raised concerns about handing the islands to Mauritius, seen as an ally of China.

Sir Keir Starmer has been left humiliated after being forced to dramatically halt the passage of a law enabling his handover of the Chagos Islands

Under the terms of Labour’s Chagos Islands deal, Britain is paying Mauritius to lease back the joint UK-US military base on Diego Garcia, which is the largest of the Indian Ocean islands

The Bill needed to implement the treaty has already been approved by MPs in the House of Commons.

Ahead of the Bill’s second reading debate in the Lords on Tuesday, the Tories put down an amendment to the committal motion, which allows the draft law to proceed to detailed scrutiny at committee stage.

The Conservative amendment demanded a 30-day consultation with the Chagossian community.

In the face of a threatened defeat, the Government pulled the procedure, effectively stalling the passage of the Bill.

Foreign Office minister Baroness Chapman of Darlington claimed the Tories were putting Britain’s national security at risk and using the Chagossian people for their own ends having ‘systematically disregarded’ them when in power.

But her Conservative counterpart Lord Callanan dismissed her claims as ‘nonsense’ and levelled the charge of ‘strategic capitulation’ at the Government.

Baroness Chapman told peers the Chagos Islands legislation ‘is vital for the security of our nation’.

She said proposals to probe the Government and amend the legislation were welcome, but added: ‘Those that are designed to wreck are not about the welfare of a community, but a cynical tactic of delay and disruption.’

‘The amendment to the committal motion favoured by Lord Callanan, is, in effect, a fatal motion,’ the Labour minister continued.

‘It makes committal conditional on consultation. It is not credible to undertake meaningful consultation in the 30-day period set out in the motion.

‘It would therefore risk progress towards ratification becoming bogged down in litigation.’

Baroness Chapman claimed the Tory plans would ‘wreck the Bill and mean a delay not of 30 days but of months, maybe years’.

‘In these circumstances, the Bill and the treaty that it is intended to implement could not move ahead. This is both reckless and deeply cynical,’ she added.

‘It is reckless because it threatens the continued operation of the base on Diego Garcia and, with that, the national security of the British people.

‘It is cynical because the opposition now seek to use, for their own ends, a community they systematically disregarded when in government.’

But Lord Callanan said: ‘We deliberately selected a short period so that the minister could not argue that we were trying to wreck the Bill – that was not our intention.

‘It was a measured, reasonable approach which we felt would have made up completely for the Government’s failure to consult the Chagossians to date and would help us in our work to give the Bill the proper scrutiny it deserves, informed by the outcome of that consultation.

‘It was not a wrecking amendment, and the minister knows that in her heart of hearts.’

He added: ‘This treaty is due to last 100 years. How is it a wrecking amendment to take 30 days to consult the people who will be affected by it? The minister is talking nonsense, and she knows it.’

Lord Callanan went on: ‘To call the Bill a surrender Bill is an understatement. This is a strategic capitulation that will see us give away sovereign territory that has been British for two centuries.

‘To add insult to injury, taxpayers are paying tens of billions to Mauritius for the privilege of doing so.’

The Chagos Islands have been a British overseas territory for more than 200 years.

But Labour insisted it had to strike a deal to protect the Diego Garcia base after the International Court of Justice ruled the UK’s administration of the islands was ‘unlawful’.