IF only one could be a fly on the wall at Buckingham Palace as the Queen reveals her thoughts on Brexit and Boris to the Duke of Edinburgh over breakfast. But Mr Johnson is only the latest in a long line of Prime Ministers who have come and gone under her reign.

How many?

Princess Elizabeth became Queen at 26 and during her 67-year reign, 14 Prime Ministers have served.

So Boris Johnson is the 14th?

Yes, and according to the ruling in the Scottish courts on Wednesday, he is the ‘first Prime Minister to advise the Queen to act unlawfully’ in relation to the proroguing of Parliament.

How does the relationship between the Queen and any PM work?

As Head of State, the Queen has always remained strictly neutral in regards to politics and is unable to vote or stand for election, so the relationship with her Prime Ministers is regarded as vital. She gives the PM a regular weekly audience during their term in office and if either the Queen or the PM are not able to meet, then they will speak by telephone.

What happens at the audience?

Her Majesty has a “right and a duty to express her views on Government matters”. These meetings, as with all communications between the Queen and Government, remain strictly confidential.

And if advice is given to the Queen?

Having expressed her views, she traditionally abides by the advice of her Prime Minister.

Who was the Queen’s first PM?

Winston Churchill, followed by Sir Anthony Eden, Harold Macmillan, Sir Alec Douglas Home, Harold Wilson, Edward Heath, James Callaghan, Margaret Thatcher and John Major. Then there was Tony Blair, Gordon Brown, David Cameron, Theresa May and now, Boris Johnson.

Did she get along with them all?

As the Queen’s views always remain private, no-one would ever know for certain, but there were rumours she wasn’t keen on the Mrs Thatcher. Declassified files revealed two years ago claimed she infuriated the Queen by defying Commonwealth leaders in an apartheid vote, refusing to back tighter sanctions against South Africa.

The Queen’s favourite?

She was very close to Churchill, who regarded her as a grand-daughter figure. His grandson, Nicholas Soames, said: “I think the Queen valued my grandfather’s experience, and he of course loved the Queen.”

A Royal household source once said: “I could not hear what they talked about, but it was more often than not punctuated with peals of laughter — and Winston generally came out wiping his eyes!” Harold Wilson called the Queen “A great support, because she is the one person you can talk to.”

So what will she make of Boris?

With her vast wealth of experience, and her recent experiences of welcoming Donald Trump on a state visit, it’s unlikely anything will faze the Monarch as such, but Boris Johnson will learn that if he is found to have misled the Queen for certain, then it could soon be time for her 15th Prime Minister.