Tory MPs will launch a last-ditch effort to block the Chagos Islands deal next week over fears it will be used by China to spy on Britain.

The Conservatives plan to force a vote in Parliament over whether to effectively kill off the deal by holding up payments to Mauritius.

The move comes as Labour is embroiled in a scandal over the collapsed China spy case, which is threatening to destabilise Downing Street.

Questions are swirling over the role of Jonathan Powell, the national security adviser, who was also an architect of the Chagos deal.

The agreement, which could cost taxpayers as much as £47bn in payments to Mauritius over the next century, has proved highly controversial.

It will see Mauritius, which has close ties to China, hand over the remote Indian Ocean archipelago, which has been British for 200 years.

The string of islands includes Diego Garcia, the site of a joint UK-US military base, which has been pivotal to operations in the Middle East.

Dame Priti Patel, the shadow foreign secretary, said: "Our spineless Prime Minister is kowtowing to China.

"He is so desperate for the CCP's approval, he is prepared to hand over his own country's sovereignty - not to mention £40 billion of taxpayers' cash - to an ally of Beijing.

"As usual, he is running scared of scrutiny. He can't face being held to account over Chagos and China, because he knows his arguments don't stand up.

"He thinks that by hiding behind the façade of international law, he can betray the British people and get away with it.

"But the Conservatives will always stand up for the national interest, and so we will resist Starmer's Chagos-China Surrender Bill every step of the way."

Concerns have previously been raised that under the deal, China could exploit its close economic ties with Mauritius to gain access to the archipelago.

As well as being used by jets, Diego Garcia is a submarine refuelling and resupply station and a hub for satellite communications in the region.

There are fears that Beijing could put a monitoring station on a neighbouring island, allowing it to spy on British and US military activities.

Legislation to approve the Chagos handover will head into its final stages in the Commons this week, with the Tories planning a last-ditch bid to thwart it.

The opposition party will table amendments to the bill, including one which would block any payments to Mauritius unless approved by Parliament.

In effect, the bill would force MPs to vote every single year to authorise annual payments of hundreds of millions of pounds to the island nation.

Another amendment would prevent the deal from coming into force unless the Government publishes Lord Hermer's legal justification for it.

Questions have been asked about the Attorney General's role in the deal and the advice that he provided to Sir Keir Starmer.

Ministers have argued the agreement is necessary because of an advisory International Court of Justice opinion, which stated the islands should go to Mauritius.

They have said that failing to sign a deal to hand over the archipelago could leave the UK vulnerable to losing future international lawsuits on sovereignty.

But critics have questioned that rationale, arguing that the ICJ has no jurisdiction or powers to force Britain to hand over the territory.