Donald Trump has arrived in the UK ahead of his three-day state visit.

The US president and his family touched down at Stansted Airport around 9am this morning and they will now head to London to meet the Queen.

Within minutes of landing, Mr Trump took to Twitter to reignite his feud with London Mayor Sadiq Khan, who branded the president a "fascist" in the days leading up to the state visit.

Mr Trump wrote: "@SadiqKhan, who by all accounts has done a terrible job as Mayor of London, has been foolishly "nasty" to the visiting President of the United States, by far the most important ally of the United Kingdom. He is a stone cold loser who should focus on crime in London, not me......

"...Kahn reminds me very much of our very dumb and incompetent Mayor of NYC, de Blasio, who has also done a terrible job - only half his height.

"In any event, I look forward to being a great friend to the United Kingdom, and am looking very much forward to my visit. Landing now."

The Trumps will head to Buckingham Palace for a reception with the Queen, the Prince of Wales and the Duchess of Cornwall.

The Duke of Sussex will also attend a private lunch at the palace - although his wife, who is on maternity leave, will be at home with their four-week-old son, Archie.

In a potentially awkward start to the trip, Mr Trump has already had to deny making "bad" comments about Meghan.

He tweeted to say that he did not brand the American former actress "nasty" when he was recently confronted with comments she made before the 2016 US elections saying she would leave the country if he won.

He blamed the "Fake News Media" for the reports and, asked at the White House on Sunday evening if he was willing to apologise to the royal family, or to clarify the comments made to the Sun's political editor, Mr Trump replied: "No, I made no bad comment. Thank you."

A string of events have been prepared to honour the couple, including a ceremonial welcome in the Buckingham Palace garden before Mr Trump has the opportunity to inspect the Guard of Honour.

Elsewhere, royal gun salutes will fire in Green Park and at the Tower of London to mark the Trumps' arrival.

They will then visit Westminster Abbey where the president is due to lay a wreath at the Grave of the Unknown Warrior.

Mr Trump and wife Melania are also due to have tea with Charles and Camilla at Clarence House.

The day is due to conclude with a state banquet at Buckingham Palace at which both the Queen and Mr Trump will give speeches.

Mr Trump's arrival in the capital is due to be followed by a protest through central London against the visit on Tuesday, with the Trump Baby blimp made for his visit last year due to put in an appearance.