President Trump meets the Queen at Buckingham Palace on UK state visit

The Queen delivered a subtle message to royal watchers while hosting the official welcome to President Trump at Buckingham Palace.

In a break from royal protocol, it was Prince Charles rather than the Queen who met the President and First Lady when they arrived on US helicopter Marine One to mark the start of their state visit.

The Prince of Wales and the Camilla, Duchess of Cornwall crossed the lawn to shake hands with their guests before guiding them up the stairs to where the Queen was waiting.

The royal welcome differs from when the Queen and Prince Philip met US President Barack Obama and Michelle Obama from their helicopter in Windsor in 2016 - and is a sign to royal watchers the 93-year-old monarch is handing more official duties to her son.

She has stopped overseas visits and Prince Philip has retired from public life.

Charles and Camilla also hosted the Trumps to tea, with a private discussion and photoshoot capped off by a cheeky wink at the cameras from Camilla.

It's unknown what Charles, a fervent environmentalist and the President, who has called climate change a "hoax", talked about during the meeting.

On Monday, the President and his wife received a 41-gun salute to mark their official welcome, with a further 41 shots fired to mark the anniversary of the Queen's coronation on June 2.

The President chatted to the monarch at the steps of the Palace, overlooking a large lawn where garden parties are usually held. He then inspected a military guard, stopping for a lengthy chat, as Charles accompanied him.

His unconventional handshake caught the eye of those watching the event unfold, with one comparing it to a "ten step ghetto handshake" and others asking whether he bowed as protocol dictates.

Ivanka Trump and Jared Kushner, along with US national security adviser John Bolton and press secretary Sarah Sanders watched the ceremony from the balcony.

After singing the US and British national anthems, the Trumps were escorted inside where they exchanged gifts and had a private lunch with Prince Harry.

It comes after the President said Meghan Markle made "nasty" comments about him in the past, when she called him "misogynistic" on a late night chat show.

The President and Melania were shown American artefacts in the Queen's gallery along with Charles and Camilla. Harry gave Ivanka Trump a tour of the room but seemed to be keeping his distance from the bombastic President.

The Trumps visited Westminster Abbey to lay a wreath at the Tomb of the Unknown Warrior and received a first edition of Winston Churchill's The Second World War as a gift from the Queen. She also gave Trump a pen set, with a specially commissioned silver box for Melania.

Earlier, Ivanka Trump said she was "looking forward" to meeting the Queen. Trump's eldest daughter and special adviser posted a picture of herself outside London's Victoria and Albert Museum ahead of the official visit.

"Today, Her Majesty The Queen will welcome @POTUS and @FLOTUS for a State Visit to the United Kingdom," she tweeted. "I am looking forward to joining the US delegation for this commemorative visit."

The President also made an unprecedented intervention into UK politics, saying Boris Johnson would make an "excellent" prime minister to succeed Theresa May when she steps down on Friday.

On Brexit, he said Britain should refuse to pay the EU a £39 billion divorce bill, send in Nigel Farage to negotiate, and leave the EU with no deal if necessary.

The visit will be marked by large protests, with five 20m banners already unveiled on a bridge opposite the US Embassy.

Amnesty International's banners on Vauxhall Bridge say "Resist sexism", "Resist racism", "Resist hate", "Resist cruelty" and "Resist Trump".

The charity's UK boss Kate Allen said: "Trump has presided over two-and-a-half years of utterly shameful policies.

"Locking up child migrants, imposing a discriminatory travel ban, decimating global funding for women's rights and withdrawing from global human rights bodies … We need to resist Trump's trashing of human rights."