The government has been temporarily blocked from concluding the Chagos Islands deal by a late-night High Court injunction.
According to Sky News, ministers had been expected to complete a deal that would have seen the UK hand over sovereignty of the archipelago to Mauritius in the coming hours.
But in an emergency injunction granted early on Thursday, brought against the Foreign Office, Mr Justice Goose allowed "interim relief" to Bertrice Pompe, who had previously taken steps to bring legal action over the deal.
Ms Pompe is a Chagossian woman who sees the deal as a betrayal of their rights.
The order, granted at 2.25am, states the government may take "no conclusive or legally binding step to conclude its negotiations concerning the possible transfer of the British Indian Ocean Territory, also known as the Chagos Archipelago, to a foreign government or bind itself as to the particular terms of any such transfer".
A hearing is expected to take place at the High Court at 10.30am on Thursday.
