After paying their respects in front of the Pope’s coffin, Prince William and Sir Keir Starmer walked side by side through St Peter’s Basilica.

It was there, somewhere under the 17th-century renaissance arches leafed in gold, that they spotted a huddle between Emmanuel Macron, Volodymyr Zelensky and Donald Trump.

Talks to end the war in Ukraine had begun in one of the most sacred sites in the Catholic Church, and they were gathering pace.

The Prince read the room and respectfully peeled away from his Prime Minister to allow him to enter negotiations.

Shortly after, Mr Zelensky and Mr Trump, the two men who had so woefully fallen out in front of the cameras in the Oval Office, would find a quiet corner to sit face-to face and hash out their differences.

The scene would form one of the most extraordinary pictures of the war and indeed of high-level global politics in years.