A bill aimed at enshrining in law the government's Chagos deal will not be debated in the Lords as previously planned.

The legislation, which would see the archipelago in the Indian Ocean handed to Mauritius with the UK leasing back a key military base for £101m a year, was due to be debated in the Lords on Monday.

But late on Friday, the Conservatives - who have long opposed the deal - tabled an amendment calling for a pause "in light of the changing geopolitical circumstances".

The government has now decided not to go ahead with the upcoming debate and said the bill will return to the Lords at an unspecified later date.

"The government remains fully committed to the deal to secure the joint UK-US base on Diego Garcia, which is vital for our national security," a government spokesperson said.

"This is irresponsible and reckless behaviour by peers, whose roles is to check legislation, not interfere with our national security priorities."

Government sources said they are considering how to respond but do believe there are ways to stop a similar tactic being deployed in the future.

The Diego Garcia Military Base and British Indian Ocean Territory Bill is currently in the later stages of parliamentary scrutiny known as "ping pong", where it bounces back and forth between the House of Commons and House of Lords as they attempt to amend elements of it.

The Tories claim passing the bill would put the UK in contravention of a 1966 Treaty agreed with the US over the islands and therefore in breach of international law.

Article 1 of the 1966 Treaty says "the territory shall remain under UK sovereignty".

The Tories have called on ministers to ensure agreement is reached with the US over the 1966 Treaty, before the bill returns to the House of Lords.

Under the terms of the proposed new Chagos deal with Mauritius, the UK will lease back Diego Garcia, the largest of the islands and home to a shared UK-US military base.

The deal sets a 24-mile buffer around Diego Garcia, where nothing can be built without UK consent.

Under the terms of the agreement - which was signed by Sir Keir Starmer last May - Mauritius would gain sovereignty of the islands from the UK, but allow the US and UK to continue operating a military base on one of the islands, Diego Garcia, for an initial period of 99 years.

The government said it would pay Mauritius an average of £101m a year for 99 years, which Sir Keir said amounted to a "net cost" of £3.4bn after adjusting for factors including inflation.

Last May, the prime minister said the UK had to "act now" or face Mauritian legal action that could interfere with the Diego Garcia base.

He said: "If we did not agree this deal the legal situation would mean that we would not be able to prevent China or any other nation setting up their own bases on the outer islands or carrying out joint exercises near our base.

"No responsible government could let that happen."

The delay to the Bill's parliamentary journey comes in the same week US President Donald Trump appeared to have a change of heart over the agreement.

On Tuesday, Trump described the agreement as a "great act of stupidity" - despite his administration having previously been content with the terms.

Before signing the deal in May last year, the UK offered Trump an effective veto, because of its implications for US security.

Allies of the president had criticised the plan, but during a meeting with Starmer in the Oval Office last February, Trump said "I think we'll be inclined to go along with your country".

After the agreement was signed, US Secretary of State Marco Rubio said Washington "welcomed" the deal.

Rubio said it secured the "long-term, stable, and effective operation of the joint US-UK military facility at Diego Garcia", which he described as a "critical asset for regional and global security."