There must have been a moment or two there where the Duke of Edinburgh had to bite his tongue. Maybe the Queen had had it bitten for him. Maybe she'd asked Barack to bring him as a gift those "fell pony bits and shanks" (this had to be repeated to us hacks three or four times). Maybe he was wearing the bits to stop saying the things he is famous for saying as they showed POTUS and FLOTUS around the displays in the Royal Collection.
They'd been together by then for four hours. A long time for the Duke to behave as well as this. We'd seen them with the Scots Guards in the garden of Buckingham Palace, heard the 21-gun salute, felt the thump of the echo. Now we were inside the Palace to look at them looking at the Royal Collection.
There were a number of of strangely moving table displays in the gallery.
On one, the diary of George III with an entry in his own royal hand saying "America is lost! Must we fall beneath the blow?" The simplicity and directness of the language is a lesson for us today, and from a hereditary king. Mind you, that's a lesson the Duke learnt years ago.
That diary entry went on to talk about the emigrants to America looking for "employment suitable to their poverty" and referred to the "10,000 Scotch pedlars in Poland" – the Duke would have had much to say on both those subjects. He refrained from doing so.
But he must have swallowed hardest of all at "the Female Society for for the Relief of British Negro Slaves". How many regulations – indeed laws – could he break with that one?
And there was the diary entry of Queen Victoria about Uncle Tom's Cabin which again brought the old girl to life in front of us, "to what can human nature descend," she asked. "Wives torn from their husbands and little children from their mothers. Too painful . . . It quite haunts me."
In the event the wicked old Duke behaved impeccably. As did they all. It was all charming: they charmed each other, and that charmed everyone.
The Queen made dry little jokes and flashed her lovely smile. The Obamas chuckled and chatted back. "We got a good deal there," he said, referring to the White House desk. "Just a temporary blip in our relationship," was another, as they worked through the War of Independence exhibits. All is well again, then. We've recovered from when Gordon Brown went over there two years ago and blipped like billy-oh. (Now there's a candidate that would put back by a century the cause of an elected head of state in Britain.)