PM says deal has secured future of US-UK military base as Conservative leadership hopefuls play blame game

Keir Starmer said securing the military base on Diego Garcia was the ‘single most important thing’. Photograph: Anthony Devlin/EPA

Keir Starmer has defended giving up UK control of the Chagos Islands, as the decision has descended into a political blame game among Conservative leadership candidates.

The prime minister said the agreement with Mauritius over the islands would secure the long-term future of a joint US-UK military base on Diego Garcia, which he deemed as the “single most important thing”.

Critics of the deal have said it could allow China to gain a military foothold in the Indian Ocean and concerns were raised about the future of other British overseas territories.

While Labour signed off on the final decision, it was the Conservatives who first indicated that the UK was open to negotiations with Mauritius, the discussions having being launched under Liz Truss.

The then foreign secretary and now Conservative leadership candidate James Cleverly opened the talks saying he had hoped to have them concluded by the end of 2023.

Labour’s decision appears to have created a split within Cleverly’s leadership campaign, with the former MP Grant Shapps, who is Cleverly’s campaign chair, noting he blocked the deal.

Shapps said on X: “As defence secretary I was so concerned about the sovereignty of the Chagos Islands that I blocked the deal from proceeding. Today, this government has announced it’s abandoned our sovereignty of the archipelago, including the militarily essential Diego Garcia.”

The former Tory prime minister Boris Johnson said it was “crazy” to give up control of the Chagos Islands. He told GB News: “Why are we doing this? Sheer political correctness, desire to look like the good guys, desire to look as though we’re unbundling the last relics of our empire.

“It’s nonsense. It’s a bad idea in hard geopolitical terms, because the base in Diego Garcia is of huge strategic importance for the US, for the west, and it’s a key component of the Anglo-American alliance. It’s one of the things we bring to the table, has been for decades.”

Truss’s spokesperson, however, blamed Johnson for the decision. “It was Boris Johnson who asked Liz to talk to [the Mauritius prime minister Pravind Jugnauth] about this at Cop26, which she did. But she was absolutely clear that we would and should never cede the territory.”

Cleverly’s leadership rival Tom Tugendhat criticised his colleagues’ role in the process, saying it was “disgraceful that these negotiations started under our watch”.

Jonathan Powell, Starmer’s special envoy for negotiations between the UK and Mauritius who brokered the deal, rejected the “silly” Tory criticism, noting Cleverly had “enthusiastically” led the talks not long ago.

When the prime minister was asked to guarantee that no other British overseas territories would be signed away under Labour, he told reporters: “The single most important thing was ensuring that we had a secure base, the joint US-UK base; hugely important to the US, hugely important to us.

“We’ve now secured that and that is why you saw such warm words from the US yesterday.”

The agreement over the continued UK-US military presence on Diego Garcia is expected to run for 99 years with an option to renew, with Britain paying an annual sum of money.