Inside Donald Trump's most talked about moments during UK visit

The high-profile two-day state visit of U.S. President Donald Trump and Melania Trump began on Tuesday, September 16.

The couple was officially welcomed by Prince William, Princess Kate, and later received by King Charles and Queen Camilla. Several engagements took place throughout the visit.

According to the pre-planned schedule, the couple's had lunch together after the ceremonial welcome at Windsor Castle and exchanged gifts.

One moment from the visit sparked controversy, as President Trump was seen allegedly breaking royal protocol by patting King Charles on the back and Prince William on the arm.

Following the footage circulating on media platforms, BBC reporter Richard Irvine-Brown addressed the situation by referencing the official Royal Family website, claiming, 'There are no obligatory codes of behaviour when meeting The Queen or a member of the Royal Family, but many people wish to observe the traditional forms.'

Richard added: 'President Emmanuel Macron of France did so in July of this year.'

This comes after First Lady Melania Trump was critisced for allegedly ignoring Queen Camilla at the state banquet.

In a clip that has gone viral, Queen Camilla seems to be speaking to the First Lady, who is instead looking away and appear to be engaged in conversation with Prince William, with royal fans quick to share their opinions.