During her 70-year reign, the Queen has asked 14 politicians to become Prime Minister and form a government on her behalf - and she's about to welcome her 15th following Boris Johnson's resignation.
The Monarch has a close relationship with whoever is living at Number 10, holding a weekly audience to get updates from Westminster.
While she keeps her political views and her opinions on each prime minister private, she's faced several awkward moments with outgoing Johnson - including a grovelling apology over Partygate.
Following the news that the Tory has finally stepped down, we look at his complicated relationship with the Queen and the rest of the royal family.
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Protocol fail in private meeting
Just minutes after entering Number 10, Johnson made his first blunder when he revealed details of his first private meeting with the Queen.
He was overheard telling staff about their chat, details of which are meant to be secret.
She reportedly told him: "I don’t know why anyone would want the job."
Weekly meetings
Every Wednesday, the Queen sits down with her Prime Minister to get an update on important national matters.
They were traditionally held at Buckingham Palace, however they moved to video calls during the Covid pandemic. They have taken place at Windsor Castle since the Monarch made it her official residence.
The meetings are held in an Audience room within her apartments and are entirely private - with most former PMs never revealing what is said during them. There are no advisers in attendance.
The Queen gave a rare insight into the meetings during a documentary in 1992. She said: "They tell me what is going on or if they have any problems, and sometimes I can help in some way as well."
"They know I can be impartial and it is rather nice to feel one is a sponge.
"Occasionally one can put one's point of view and perhaps they have not seen it from that angle."
Grovelling apology
Johnson was forced to apologise to Her Majesty after it emerged staff parties had been taking place in Downing Street the night before her beloved husband Prince Philip's funeral.
At that time, Covid restrictions banned mixing indoors with anybody, not in your household or support bubble, which severely impacted Philip's funeral.
The service was limited to just 30 guests and heart-wrenching pictures on the day showed the grieving Queen, following the rules and sitting alone in St George's Chapel due to social distancing rules at the time.
Balmoral holiday
As is tradition, Johnson and his family have joined the Queen and members of her family at the royals' Balmoral estate in the Scottish Highlands for a private holiday.
They had fewer trips due to the Covid pandemic, however enjoyed breaks in 2019 and 2021.
For the 2021 break, Johnson was joined by wife Carrie, who was pregnant, and the couple's son, Wilfred.
Speaking at the time, the PM's spokesman said: "The PM was in Balmoral over the weekend. It was an entirely private visit."
Balmoral is said to be one of the Queen’s favourite places, holding a special place in her heart as it is the castle where Prince Philip proposed to her.
Warning over visit
Another potentially uncomfortable chat could have been last year, when the PM's former chief aide Dominic Cummings claimed Mr Johnson wanted to visit the Queen in person early in the coronavirus pandemic despite Downing Street staff already falling ill with Covid-19.
The former chief aide in No 10 told the BBC he had to convince the Prime Minister out of visiting her by warning about the potentially grave consequences.
Mr Cummings, who has been engaged in a war of words with Mr Johnson since leaving No 10 in November 2020, alleged the PM wanted to visit her on March 18, 2020.
"I said, what are you doing? And he said, I'm going to see the Queen and I said, what on earth are you talking about, of course, you can't go and see the Queen," Mr Cummings said in an interview.
"He said, ah, that's what I do every Wednesday, sod this, I'm gonna go and see her.
"I just said if you go, if you give her coronavirus and she dies what, what are you gonna, you can't do that, you can't risk that, that's completely insane."
Downing Street denied the incident - first reported by the Mirror - took place while Buckingham Palace declined to comment.
