Shadow foreign secretary Andrew Mitchell also criticised the move as ‘not a deal’ which previous Conservative foreign secretaries would have struck.

The government of Mauritius has long argued that it was illegally forced to give the Chagos Islands away in return for its own independence from the UK in 1968. At the time, the British government had already negotiated a secret deal with the US, agreeing to lease it the largest atoll, Diego Garcia, for use as a military base.

After years of legal wrangling and negotiations, Britain said it would surrender sovereignty of the archipelago in the Indian Ocean.