DAME Priti Patel has demanded an immediate U-turn by the PM over his deal to surrender the Chagos Islands.
It comes after Sir Keir Starmer’s offer was rejected by the new leader of Mauritius.
Navinchandra Ramgoolam said he wants even more cash.
Sir Keir has pledged to pay millions to lease back the strategically important Indian Ocean isles, including Diego Garcia where the US has a vital military base.
However, US President-elect Donald Trump is known to be furious amid fears of Mauritian links to China.
Meanwhile, Mr Ramgoolam’s deputy accused Britain of “nit-picking about the compensation”.
READ MORE ON CHAGOS ISLANDS
Last night, Shadow Foreign Secretary Dame Priti said: “While Labour ministers refuse to answer straight-forward questions in Parliament about the Chagos surrender, the Mauritian government has let the cat out the bag.
“They’ve confirmed that Labour wants the deal done before President Trump returns to office, and they want more British taxpayers’ cash.”
Sir Keir aims to stand by a 2019 UN ruling that the British-run islands belong to Mauritius.
Among countries voting in favour were Russia, China, North Korea, Belarus and Syria.
After talks with US Foreign Secretary Anthony Blinken, Mr Ramgoolam said: “I made him understand we do not agree with certain things contained in the original agreement by the former (Mauritian) prime minister.
“We will continue to negotiate.”