America's cable news shows have been offering rolling coverage of Donald Trump's State Visit to the UK, revelling in the pomp and circumstance of the occasion with 'royal experts' on hand to guide viewers through every nod and handshake.

But the outlets are also on high alert for signs that the US president is ignoring protocol or prompting a diplomatic storm, after he gave a newspaper interview in which he weighed into the Tory leadership race and appeared to criticise the Duchess of Sussex. As one CNN commentator put it, "he's a bull carrying a china shop on his back".

There is a consensus that Mr Trump is eager not to put a foot wrong during his royal engagements and Melania Trump, the First Lady, has reportedly spent a great deal of time studying up on royal etiquette ahead of the three-day visit.

American commentators have spent the day recounting mistakes made by previous heads of state - president Jimmy Carter famously broke protocol by kissing the Queen Mother on the lips, and much was made of former First Lady Michelle Obama putting her arm around the Queen in 2009.