The Tory leader says Labour's negotiations could cost the UK billions; the prime minister questions whether Badenoch has been "properly briefed" on UK security.

Britain struck a deal in October to cede sovereignty of the Chagos Islands to Mauritius - a former colony that became independent in 1968 - while retaining control under a 99-year lease of the military base on Diego Garcia, the largest island of the Chagos Archipelago.

A Labour minister has squirmed under pressure after being questioned about the Government's plans to hand over of the Chagos Islands as well as billions of pounds. The British Indian Ocean Territory includes a crucial naval base on land leased by the United States from the UK military. Since 1971. Only the atoll of Diego Garcia has been inhabited