The pair went to Buckingham Palace for a private lunch and welcome ceremony.

Mr and Mrs Trump laid a wreath at the tomb of the unknown warrior in Westminster Abbey and are due to attend a state banquet this evening.

Minutes before arriving in the UK, Mr Trump criticised the Mayor of London, with whom he has clashed in the past.

He tweeted that Sadiq Khan - who had earlier said the UK should "not roll out the red carpet" for Mr Trump - was a "stone cold loser", but the president added he was looking forward to his visit.

Mr and Mrs Trump arrived on Air Force One earlier on Monday and were taken to the US ambassador's home in central London, where they are staying, before travelling to Buckingham Palace.

Protests are planned in several UK cities during the three-day visit, including in London, Manchester, Belfast, and Birmingham.

Labour leader Jeremy Corbyn - who is boycotting the state dinner - is due to attend and speak at the London demonstration, a party spokesman has confirmed.

Earlier, Mr Corbyn tweeted: "Tomorrow's protest against Donald Trump's state visit is an opportunity to stand in solidarity with those he's attacked in America, around the world and in our own country - including, just this morning, Sadiq Khan."