Keir Starmer was hammered over ‘surrender’ on the Chagos Islands today during bad-tempered PMQs clashes.

The premier was accused by Tory leader Kemi Badenoch of handing Mauritius the British territory ‘so north London lawyers can boast at their dinner parties’.

But Sir Keir insisted there was a need for ‘legal certainty’ over the status of the military base on Diego Garcia – saying the deal was needed for ‘national security’. 

The exchanges came amid signs the PM faces a Cabinet revolt over the ‘mad’ proposals.

There are claims that the agreement to hand over sovereignty will involve the government paying Mauritius up to £18billion.

That would be for a 99-year lease to host the strategically crucial military base – although much of the sum would be front-loaded.

However, Labour alarm at the prospect of the pact has been mounting, with fears the ‘terrible’ arrangement will be a gift to Reform and ‘impossible to understand’.

Fingers are being pointed at Sir Keir himself and his close friend Lord Hermer, the Attorney General, who is said to have been involved in talks. 

The pair are both former human rights lawyers. There have been long-standing questions about the status of the Chagos Islands under international law – although many critics dismiss the sovereignty disputes.

Ms Badenoch told the Commons: ‘When Labour negotiates, our country loses. Yesterday, we heard the Government offered £18billion for Mauritius to take our territory in the Chagos Islands.

‘This is money that belongs to our children and their children. This is an immoral surrender so North London lawyers can boast at their dinner parties.’

Sir Keir said: ‘This is a military base that is vital to our national security.’

He later continued: ‘A number of years ago, the legal certainty of that base was thrown into doubt. Let me be clear and I’ll pick my words carefully, without legal certainty, the base cannot operate in practical terms as it should.

‘That is bad for our national security and it’s a gift to our adversaries.’

Ministers have been denying that the £18billion figure is right. 

One senior government source told the BBC: ‘At a time when there is no money, how can we spend billions of pounds to give something away?’ 

A Labour backbencher told MailOnline: ‘It feels like nobody has thought how this will look to the average person.

‘Reform will go around saying there was no money for the winter fuel allowance but there’s billions for this deal. It makes fighting them so much harder.’

Answering questions in the Mauritian National Assembly yesterday, Navin Ramgoolam said Sir Keir had discussed the prospect of a deal with him in a telephone conversation on Friday.

And he said Sir Keir wanted to ‘push ahead’ with a deal that would including giving Mauritius a veto on extending a proposed 99-year lease on the strategically important Diego Garcia airbase used by the United States.

Critics including senior figures in the Trump administration and on the opposition benches in the Commons have warned that the handover risks giving a powerful boost to China in the Indian Ocean.

The UK had reached an agreement on returning sovereignty over the Chagos Islands to Mauritius with the previous Mauritian government last year, but Mr Ramgoolam insisted on renegotiating the deal when he came to power in November. 

A renegotiated Chagos deal, which Mr Ramgoolam said confirmed Mauritian sovereignty over the islands and required mutual agreement to any extension of the lease on Diego Garcia, is currently being reviewed by the Trump administration.

Mr Ramgoolam told the National Assembly: ‘President Trump is not a wolf. Let him see if the agreement is good or not.

‘Now the British have, late in the day, decided that, yes, it is better to let the new administration have a look, that is what the situation is.’ 

Asked about the reported costs of the deal, Mr Reed told Sky News: ‘Clearly when this Government came in negotiations were already under way about the future of that base and its future was not secure.

‘Our priority is security, of course, so those negotiations continue. There were some figures that were being [..] I read them, I’m sure your viewers did too yesterday. The Foreign Office has confirmed those figures were wrong but we need to wait and find out exactly where these negotiations end up before we’ll know for certain.’

Pushed on the potential impact of the payments to Mauritius on the Government’s so-called economic black hole, Mr Reed added: ‘We have to secure the future of that military base. It’s in a very important strategic location globally.

‘It’s not just the UK, of course, that has an interest here, so does the US, and the Government is making sure that we hear the views of the US before we take a final decision.

‘But we need to wait and see what the final outcome of those negotiations are, but I can confirm those rather extraordinary figures we heard being banded around yesterday are not correct.’