As MI6 chief and a former ambassador to Turkey, Sir Richard Moore is equipped with the sort of front-line foreign policy expertise and diplomatic skill that has put him at the top of the shortlist to become the UK’s man in Washington.

His intelligence role means he is fully vetted – without any hint of the sort of embarrassing history that brought down Lord Mandelson, who was sacked last week over his links to Jeffrey Epstein, the convicted paedophile.

On Wednesday night, Sir Richard could take a major step closer to being appointed British ambassador to the US. He will be among the guests invited by the King for a state banquet honouring Donald Trump at Windsor Castle.

All eyes will be on Sir Richard to see how he gets along with the mercurial US president, according to a source familiar with the process of selecting the new ambassador.