David Lammy will meet Donald Trump’s secretary of state in a last-ditch effort to convince the US to back the Chagos Islands deal, The Telegraph understands.

The Foreign Secretary is expected to meet Marco Rubio, his US counterpart, later this month. He will address fears that handing the islands to Mauritius will make it easier for China to spy on America.

The fate of the UK’s proposal to hand control of the islands to Mauritius is in the balance as Mr Trump’s team have now been given full details, allowing line-by-line scrutiny.

Close allies of the US president have urged Mr Trump to shred the deal for fear it could be exploited by Beijing to spy on the US military base on Diego Garcia, one of the islands.

But the Foreign Secretary is expected to try to ease spying concerns and convince Mr Rubio to back the deal when they meet at the Munich Security Conference in two weeks’ time.