Has anyone loved being Prime Minister as much as Boris Johnson? Robert Peston asks

I’ve learned only one thing at the G7 summit of big rich countries here in Biarritz: Boris Johnson absolutely loves being Prime Minister.

There’s little of the conspicuous sense of duty that weighed on the shoulders of Theresa May, Gordon Brown and Sir John Major.

Nor is there that unnerving claim to embody the spirit of a nation that Tony Blair and Margaret Thatcher perhaps made too often and believed too much.

There’s a touch of David Cameron’s Old Etonian entitlement, the idea that it would be odd if he weren’t PM.

But mostly Johnson simply seems to be having fun - whether by pointing a joshing finger at the imperious president of France or telling an incredulous President of the EU that they agree on absolutely everything.

• Watch Robert Peston's full interview with Boris Johnson

Johnson’s bonhomie is all the more odd because the UK - as his advisers remind him continuously - is in the grips of the most acute peacetime crisis for generations, over how and even whether to leave the EU, and Johnson’s grip on power is almost non-existent, with no majority in Parliament and fratricide in his own Tory party as unremarkable as shaking hands.

But in Johnson we have the clown prince of prime ministers, who - for the first time in years, or perhaps ever - plainly thinks he is home.

His interlocutors - Emmanuel Macron, Donald Tusk, Justin Trudeau - all laugh.

With him or at him? I am not sure that matters, in that he seems to cheer them up.

Crass buffoonery it is not.

He has astutely allowed Trump to adopt him as his protege, while conspicuously siding with the rest of the world against Trump’s protectionist, mercantilist war with China and Trump’s attempt to starve and humiliate Iran with sanctions.

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Johnson’s time at the top could yet be the shortest in history, if the MPs who hate his seemingly remorseless march to a no-deal exit from the EU have their way.

But he is absolutely determined to enjoy himself - and to try his damnedest to represent a full-stop to the austerity of the Cameron/Osborne era and the anxiety of the May years.

Many of you, perhaps most of you, will say that little of what’s happening in the UK and in the world is a laughing matter, and you would be right.

Many of you will recoil at the sangfroid with which Johnson is severing so much of what binds us to the continent of Europe.

Equally it is obscenely premature to assess whether Johnson is the embodiment of an England cricket team that two days ago suffered its worst ever batting collapse or on Sunday enjoyed its greatest ever comeback - or indeed something altogether more ordinary.

But as you may have seen from my interview with him on Sunday, high office at a time of emergency has not cowed him in the way it did most of his predecessors.

For better or worse, Johnson is different.