LONDON, April 28. /TASS/. US President Donald Trump breached royal protocol by tapping King Charles III on the shoulder, The Daily Mail reported, describing the meeting between the British monarch and Queen Camilla with the American leader and First Lady of the United States Melania Trump.

The violation of the unwritten rule that one should not be the first to initiate physical contact with a member of the royal family happened as the royal couple arrived at the White House on the first day of their state visit.

Video footage showed that after shaking hands and posing for official photographs, as both couples were walking toward the US president’s official residence, Trump delicately touched the monarch on the shoulder.

Body language expert Judi James told the Daily Mail that the touch was technically a breach of royal protocol, but King Charles did not seem to mind. "Charles has always seemed more relaxed about that than his mother [Queen Elizabeth II]," she said. James called the incident a "political gesture" showing the US leader’s goodwill.

The first state visit by a British monarch since 2007 will continue until April 30.