Video report by ITV News Royal Editor Chris Ship
Donald Trump won’t be the first controversial leader to be hosted by The Queen during a formal State Visit to the UK.
The invitation might come from Buckingham Palace, but it’s never the Queen who decides who will and who won’t come on these grand ceremonial occasions.
The Foreign Office normally concludes which leader it would like to come here based on the government's economic and political priorities at the time.
Theresa May for example, was keen to rush out an invitation when she visited the White House shortly after Mr Trump was elected.
But as the constitutional Monarch and Head of State, it falls to the Queen to lead the country’s welcome on a State Visit.
Before them, it was the Presidents of Colombia, China and Mexico.
The most recent US President to come on a State Visit was Barack Obama and his wife Michelle in 2011.
George W Bush, also a controversial US President for many in the UK, came here on a State Visit in 2003.
Donald Trump’s formal visit has been put off several times over fears of large scale protests, but he did come on a short "working visit" last year when he met the Queen at Windsor Castle before playing golf at his Turnberry resort in Scotland.
But, be they high-profile and contested or low-profile and benign, the visitor on a State Visit to the UK is accorded the same ceremonial welcome.
Donald Trump’s official welcome after Air Force One has landed (usually at Stansted Airport for security reasons) will be on Horse Guards Parade.
There, Mr Trump and the First Lady, Melania, will be greeted by the Queen and other members of the Royal Family.
The president will be invited to inspect a guard of honour.
Then he will accompany the Queen as a carriage runs along The Mall to Buckingham Palace in a procession of mounted soldiers from the Household Cavalry.
Mr Trump is expected to ride in his Cadillac - the president state car dubbed 'The Beast' which is his security team's preferred mode of armoured travel.
The arrival at the Palace is usually welcomed with gun salutes fired from nearby Green Park and the Tower of London.
On the evening after the arrival of the Trumps, the Queen will host a State Banquet - an opulent and lavish affair in the Ballroom of Buckingham Palace.
The Prime Minister and key politicians from all parties are invited.
As leader of the Her Majesty’s Opposition, Jeremy Corbyn will receive an invitation.
Given he took part in protests when Donald Trump last came to the UK, that will prove to be a tricky diplomatic and political moment for Mr Corbyn.
The Queen will make a speech to the 150 assembled guests before proposing a toast to Mr President.
Donald Trump replies and proposes a toast to Her Majesty.
Few details of the visit have been released and many will remain under wraps until nearer the time, though we know that Mr Trump will visit from Monday, June 3, to Wednesday, June 5, and he will not be sleeping as a guest at Buckingham Palace.
But Mr Trump will have meetings in Downing Street (as it’s a dead end, the street always proves to be a difficult moment of manoeuvring for the driver of The Beast!).
The UK-US’s so-called "special relationship" is usually affirmed in the press conference which follows.
We wait to see whether the Speaker of the House of Commons, John Bercow, will allow Mr Trump to address the Houses of Parliament.
Whilst many visiting Heads of State do, Mr Bercow has previously said the address to MPs and Lords is "not an automatic right, it is an earned honour".
And there are certainly those in the Commons entirely opposed to the president's arrival.
Labour's shadow foreign secretary Emily Thornberry firmly criticised the visit when it was announced on Tuesday, saying: "It beggars belief that on the very same day Donald Trump is threatening to veto a UN resolution against the use of rape as a weapon of war, Theresa May is pressing ahead with her plans to honour him with a State Visit to the UK.
"This is a President who has systematically assaulted all the shared values that unite our two countries, and unless Theresa May is finally going to stand up to him and object to that behaviour, she has no business wasting taxpayers’ money on all the pomp, ceremony and policing costs that will come with this visit."
[Queen welcomes US President Donald Trump to Windsor Castle as part of his whirlwind UK tour](http://Queen welcomes US president Donald Trump to Windsor Castle as part of his whirlwind UK tour)