A so-called “killer clause” of the Chagos Islands Treaty grants the Government power to make any amendments without consulting Parliament, a bombshell report has claimed.

Critics say Clause 5 of bill, made in connection with the UK-Mauritius deal signed by Sir Keir Starmer in May, enables the Government to change any part of the agreement by “Order in Council”, bypassing the need for a vote or any dispute.

Campaign group Stand for Our Sovereignty dubbed it “Killer Clause V”.

Citing the clause, it said the Government is granted the power to “make any provision that appears to his Majesty to be appropriate as a result of the Treaty”.

Conservative MP Sir Iain Duncan Smith has slammed the Bill as “appalling” and called for it to be rethought.

He said: “Absolutely everything can be changed by Orders in Council, with no vote and no dispute. If the Government decide to go in a different direction, they do not have to consult Parliament any more.

“The sweeping powers in the Bill are ridiculous.”

The Chingford and Woodford Green MP added: “Even by the standards of previous Governments, this Bill is pretty astonishing. It is a massive sweep.

“This is not really democracy any more; it is monocracy.

“In other words, we have given up debate and dispute, and we have handed things over to one person—the Prime Minister.”

It comes just a day after GB News reported on a letter signed by over 40 senior MPs, peers, former ministers, and national security leaders calling on Donald Trump to stop the Chagos Islands agreement.

The “surrender deal”, as it has been dubbed by its critics, saw Sir Keir hand over sovereignty of the Chagos Islands to Mauritius while keeping the UK-US military base on Diego Garcia on a 99-year lease.

In a letter delivered this week by the Great British PA, the signatories warn that the move would “gravely undermine” both UK and US security interests by threatening the future of the Diego Garcia military base, a facility described as the cornerstone of America’s nuclear and naval power projection in the Indian Ocean.

The group argues that transferring the Chagos Archipelago to Mauritius would place Diego Garcia under the jurisdiction of a state bound by the Pelindaba Treaty, Africa’s nuclear-weapon-free zone agreement.

They warn this could create “dangerous legal ambiguity” over US nuclear-capable operations, exposing them to challenges from China, Russia, or international bodies.

Notable names that signed the letter – reported on by Facts4EU and shared exclusively with GB News – include former Tory leader Sir Iain Duncan Smith, former home secretary Suella Braverman and Sir Grant Shapps, the ex-defence secretary.

A Labour MP, peers, military veterans, legal experts and national security professionals have also signed.

The Government has insisted the agreement “secures this vital military base for the future”.

The letter reads: “Mr President, you have built your reputation on refusing to cede strategic ground to those who would weaken America.

“We urge you to use your influence, publicly and privately, and your prerogatives under the US-UK defence agreement of 1966 to oppose this surrender and to ensure that Diego Garcia remains exempt from any constraint under the Pelindaba Treaty.”