Gordon Brown has admitted he could be left “embarrassed” during meetings with the Queen.
The former prime minister revealed that Queen Elizabeth II was often better informed about current affairs than he was.
He recalled how the Queen questioned “why have these bankers got it all wrong” in 2008, when the financial crash led to the UK entering recession.
Brown, who was the Labour prime minister between 2007 and 2010, said the Queen “actually knew better about what was happening to the country” than he did during his time in No.10.
He told the BBC’s Sunday with Laura Kuenssberg show: “She would listen, she would ask questions. She would be endlessly knowledgeable about everything happening in the Commonwealth.
“I was very embarrassed one day because I went in to see her at six o’clock, I didn’t know that one of the Commonwealth leaders had been ousted and a new government had been formed.
“She was telling me what was happening when I was supposed to report to her.”
While he had been in the Commons all afternoon the Queen would be keeping herself up to date by watching television and “getting notes from her secretaries”.
He added: “She actually knew better about what was happening to the country than I was. It was quite embarrassing.
“It just showed how conscientious she was, how well up on the detail, I think right to the last.
“You could see that in the meeting she had with Liz Truss when she became prime minister and Boris Johnson when he left, she could perform the duties right up until the end.
“She listened and she asked questions. I remember famously she asked ‘why have these bankers got it all wrong?’ in 2008.”
However, he stressed that the Queen would “never impose her will” on the prime minister.
“This is the modern monarchy and I think she set the tone for what King Charles and the other monarchs will do,” he said.
Brown was among the six living former prime ministers who attended Saturday’s Accession Council meeting where Charles III was formally declared as the new King.