NET migration figures published on Thursday could top the historic 606,000 high seen last year.
Downing Street is braced for “dire” border data published less than 24 hours after the Autumn Statement.
Some at the top of Government even believe the number of arrivals compared to the number of departures from Britain in the year to June 2023 could exceed 700,000.
Another record breaking hike in legal arrivals would be a hammer blow to Rishi Sunak who is already battling claims he has lost control of illegal migration.
It was suggested to the Office for National Statistics that they delay releasing the provisional figures to avoid clashing with Jeremy Hunt’s Autumn Statement on Wednesday.
But the ONS last night confirmed publication would go ahead on Thursday morning.
The snapshot of the last half of 2022 and the first half of 2023 would include a large number of Ukrainian refugees, and a surge in visa applications this year.
A Whitehall source told The Sun: “The figures are going to be dire.” Another source added the figures were “Up, always up.”