Theresa May has said the late Queen was the "most remarkable person" she had ever met, as she described the audiences with her as "moments of calm" in an otherwise frantic political landscape.
The former Conservative prime minister said the combination of qualities Her Majesty possessed were so unique she doubts she will ever meet anyone else like her again.
"She was the most remarkable person I have ever met," Mrs May told ITV's Lorraine on Tuesday morning.
"The combination of qualities that she had, I have not come across in anybody else. I doubt we will see her like again."
"I will remember so many moments with her. I think particularly some of those moments at Balmoral, where she felt more able to relax and we were able to relax in her company."
'I doubt we will see her like again,' Theresa May said of the late Queen
The former PM, who was in post from 2016 and 2019, said the late Queen had a great sense of humour and sense of fun, remaining down to earth despite her duties as head of state.
She added the continuity of her as monarch was hugely important and "unprecedented", with the Queen able to give helpful advice after accumulating so much experience over the decades.
"Yes, she had this very significant role and was very conscious of the responsibilities that she had as our constitutional monarch," she went on to say.
"But she always wanted to put people at their ease and wanted to calm people's nerve. And the sense of fun was enormously helpful in that for a lot of people I know."
Mrs May described a dream her husband Philip had about the Queen, in which she was driving him in a Range Rover along the Balmoral estate in Scotland, which was said to be her favourite refuge.
"The Queen was driving and the passenger in the front seat was his wife, the prime minister. Then he woke up and he realised it was reality!" the former Tory leader quipped.
Coming to the throne in 1952, aged just 25, the Queen had seen 15 prime ministers during her 70-year reign as British monarch, the first being Winston Churchill.
Mrs May, who was the 13th, said the first audience as prime minister with the Queen impresses the seriousness of the role for newly elected leaders and carries with it a tremendous sense of history.
She said she treasured her audiences with her - which are private and not recorded - as it was a brief period of quiet amid what were usually "incredibly frenzied times".
"Those audiences were a moment of calm, which was enormously helpful for prime ministers," she told ITV.
But she also admitted the first occasions meeting her were daunting and "pretty intimidating" as newly elected PMs are not sure what the nature of the conversation will be.
Last week, Mrs May, the MP for Maidenhead, shared a funny anecdote of the time she dropped some cheese in front of the Queen, as she paid tribute to the late monarch in the House of Commons.
In a personal and emotional speech, Mrs May recalled a picnic at Balmoral, detailing how she employed the three-second rule with some cheese in the presence of the Queen.
The Maidenhead MP said: “Her Majesty loved the countryside, and she was down to earth and a woman of common sense. “I remember one picnic at Balmoral, which was taking place in one of the bothies on the estate. The hampers came from the castle, and we all mucked in to put the food and drink out on the table. “I picked up some cheese, put it on a plate and was transferring it to the table. The cheese fell on the floor. I had a split-second decision to make.” Mrs May paused as MPs burst into laughter, before adding: “I picked up the cheese, put it on the plate and put it on the table. I turned round to see that my every move had been watched very carefully by Her Majesty the Queen. “I looked at her. She looked at me and she just smiled. And the cheese remained on the table.”
The remarkable life of the Queen remembered in our latest episode of What You Need To Know