Sir Keir Starmer has defended the controversial Chagos Islands deal after the Conservative leader branded it an "immoral surrender". The Government plans to give the British Indian Ocean Territory back to Mauritius and pay to lease the strategically important US-UK military base on the largest island, Diego Garcia. But questions have been raised about the skyrocketing cost of the deal amid suggestions it could cost Britain up to £18 billion.

Kemi Badenoch began Prime Minister's Questions on Wednesday by telling the Commons: "When Labour negotiates, our country loses.”. She added: “We heard the Government offered £18 billion 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.". An interim deal on returning sovereignty of the islands while maintaining the key military base was agreed last year. But Mauritian Prime Minister Navin Ramgoolam demanded to renegotiate the plans after he was elected in November.

Concessions offered to Mauritius by the UK are reported to include doubling the initial £9 billion for the 99-year lease of the Diego Garcia military base. But the alleged mounting costs are said to have left some senior Labour MPs alarmed with one branding it a “gift” to political rivals. Prime Minister Sir Keir said: "This is a military base that is vital to our national security.". He added: "If the Leader of the Opposition is properly briefed on the national security implications when she's asking these questions, which she's perfectly entitled to do, then she knows exactly what I'm talking about in terms of national security and legal certainty.

"If, on the other hand, she's not properly briefed on the national security implications, she's not doing her job, she's not concerned about national security, and she's not fit to be prime minister.". Earlier Environment Secretary Steve Reed said that the £18billion figure is "not correct", but he could not say what the final costs would be. He 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. 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.". Speaking to MPs in the nation’s capital of Port Louis earlier this week, Mr Ramgoolam claimed the deal gave Mauritius “complete sovereignty” over the island of Diego Garcia and Sir Keir Starmer had effectively doubled the amount originally offered for the lease.