Liz Truss informed early Thursday that Queen could die that day

Liz Truss already knew the queen was on point of death when she stood to unveil her £100billion energy price plan in the House of Commons on Thursday morning, it emerged.

The first indication that most people knew something was wrong came when Chancellor of the Duchy of Lancaster Nadhim Zahawi showed Ms Truss a note in the Commons at around 12.15pm, around 15 minutes before the official announcement of the Queen's poor health from Buckingham Palace.

But it is now understood that the Prime Minister was briefed by Cabinet Secretary Simon Case about the serious situation around two hours before c begin his crucial speech at 11:40 a.m.

Mr. Case, former private secretary to Prince William, told Ms Truss at around 9.30am that he had been informed by the Palace that the monarch was seriously ill and that it was "a matter of hours, not days", according to a report by the Mail on Sunday which was not challenged by Downing Street.

"The mood was one of shock, immense sadness and disbelief" , a source told the newspaper. "We started the day preparing for one of the biggest economic interventions in British history and ended it by marking the accession of a new king."

RecommendedLiz Truss caps energy bills until 2024Liz Truss joins King Charles on tour in the UK during the national mourning Queen's death - latest: Coffin leaves Balmoral for Edinburgh as huge crowds gather at Buckingham Palace