Sir Keir Starmer has told the Mauritian leader that the deal to give away the Chagos Islands must not aid China’s “malign influence”.

The Prime Minister also urged Mauritius to ensure the deal allows “strong protections” for the key Western military base on Diego Garcia during the conversation with his counterpart, Navin Ramgoolam, on Friday.

The fate of Sir Keir’s proposed agreement is hanging in the balance as Donald Trump’s team scrutinises the terms of the deal.

The Prime Minister had attempted to rush through the agreement before Mr Trump’s administration came to power, but Downing Street has since conceded that the US president has a right to look over it.

Under the terms of the deal, Britain would hand over control of the Chagos Islands – a strategically important archipelago in the Indian Ocean – to Mauritius and then lease back Diego Garcia to the UK for 100 years at a cost of £9 billion.

However, No10 has accepted that Mr Trump in effect has a veto over the agreement, given it is designed to ensure that the US military base on Diego Garcia is secure.