Boris Johnson has said the Queen never mentioned the Partygate scandal during their weekly meetings - even after it emerged No10 staff had partied the night before Prince Philip's funeral.
The former Prime Minister, who was one of the late monarch's last visitors when he travelled to Balmoral last Tuesday, said she was "bright and focused" two days before her death.
Mr Johnson described his weekly audience with the Queen as "a fantastic break from everything else".
When asked by the BBC's Fiona Bruce "got past" the revelation that a rule-breaking party had happened in Downing Street the day before the Queen sat alone at her husband's funeral, he said: "Because of her great sense of constitutional function she never got into that sort of conversation."
Heartbreaking footage showed the Queen forced to sit alone during the Duke of Edinburgh's funeral, with family members unable to console her because of Covid regulations.
It later emerged that the previous evening, No10 staff were said to have held such a raucous party for two colleagues that they broke a garden swing used by the PM's son, Wilf.
Mr Johnson told the BBC : "She was really absolutely focused on what she saw as the important issues. It's a very trusting environment, the audience with Her Majesty. So that never came up."
However he did say that he and the late Sovereign discussed "just about everything under the sun".
Their final meeting happened last Tuesday, when he tendered his resignation just before successor Liz Truss was invited to form a government.
Mr Johnson, who was ousted following a mass walkout by MPs at the start of July, said: "Given how ill she obviously was, how amazing it was that she be so bright and focused. It was a pretty emotional time."
The backbencher said he was impressed by the Queen's "sense of duty", describing her as "Elizabeth the Great."
He said her address to the nation during the first lockdown in April 2020, when she invoked the spirit of the Blitz, was "incredibly important".
Mr Johnson said he felt "this slightly inexplicable access of emotion" when he learned of the Queen's death.
On Friday the recently-ousted PM - the 14th of the Queen's 70 year reign - paid tribute to her in the House of Commons.
He recalled the Queen's "glee" when she found out a world leader had thought her 2012 Olympic opening ceremony stunt was real.
The monarch, then aged 85, melted hearts all over the world when she was filmed with Daniel Craig in the video for the landmark Games.
She was filmed supposedly jumping from a helicopter in a dramatic arrival at the Games, which were held in London, in a sequence directed by filmmaker Danny Boyle.
At a special session in the House of Commons to pay tribute to the Queen, Mr Johnson - who was Mayor of London at the time - told MPs: "I remember her innocent joy more than ten years ago after the opening ceremony of the London Olympics when I told her that the leader of a friendly Middle Eastern country seemed actually to believe that he had jumped out of a helicopter in a pink dress and parachuted into the London Stadium."
He said: "I remember her equal pleasure when I told her she'd been a success in her performance with Paddington Bear."
Mr Johnson, opened his speech - the first time he has addressed the House from the backbenches since quitting the top job - by stating: "A few months ago the BBC came to talk to me about Her Majesty.
"They requested that I should talk about her in the past tense, and I'm afraid to say I choked up, I couldn't go on.
"I'm not easily moved but I was so overcome with sadness that I had to ask them to go away."
Describing their last meeting, Mr Johnson said: "She was so radiant and knowledgeable and fascinated by politics as ever and as wise in her advice as anyone I know."
