A listener to the fun podcast The Rest Is Entertainment asked the two presenters, Richard Osman and Marina Hyde, to name ‘the coolest people in showbusiness’.

The pair agreed that Keanu Reeves and Harrison Ford are both still cool – but that the comparative youngster Timothee Chalamet (pictured bottom with Kylie Jenner of the Kardashian clan) may be sweet, but not cool.

‘The Kardashians are the least cool people in the world,’ said Hyde, adding that they were in fact so contagiously uncool that: ‘You can’t go out with a Kardashian and still be cool.’

They discussed the sad category of the formerly cool. Johnny Depp used to be cool as did Angelina Jolie, but no more. They thought Madonna was cool until she married Guy Ritchie. This was, said Hyde, ‘the female equivalent of going out with a Kardashian’.

They agreed, too, that rock star Patti Smith (top right) remains cool at 78.

This accords with my own experience. I was in a concert hall watching Patti reading her solemn and not-particularly-good poems when a young man walked to the edge of the stage and started telling her in a very loud voice that he wasn’t enjoying himself. Patti stayed as cool as can be. ‘That’s okay’, she said, in a soothing tone. ‘That’s your right.’

This disarmed the young man, who calmed down, allowing her to carry on reciting her poetry uninterrupted.

After a lot of agreement – Serge Gainsbourg cool, Steve McQueen cool, Roger Moore ‘so not cool that he’s actually cool’ – Hyde and Osman came to blows over Pierce Brosnan. Osman considered him ‘the coolest man I have ever met in my life . . . he is such a gentle, thoughtful soul and spends his time painting’.

Hyde disagreed. ‘But that’s nice. That’s not cool.’

At this point, an argument broke out over the definition of cool. Osman kept expanding the definition to include all sorts of people previously considered too cosy or unglamorous to be cool. ‘Victoria Wood is one of the coolest people I ever met,’ he said. Hyde thought this absurd. ‘I think she was utterly amazing and a genius . . . but I don’t think she’s cool. It becomes a meaningless word that applies to anyone you quite like.’

But Osman pushed on, declaring Stephen Hendry cool. ‘The reason is because he comes across as very uncool on television. And when you meet him, it’s very different. He is very cool, especially for a snooker player.’

At this point, I felt his thesis start to crumble. To say that someone is very cool ‘especially for a snooker player’ is like saying Tinky-Winky is cool ‘especially for a Teletubby’.

Of course, coolness is linked to fashion, and fashion changes. It’s clear that the traditional notion of cool – handsome, detached, unsmiling – needs updating. After all, James Bond hasn’t been cool for at least 25 years. In the 21st century, a middle-aged man in a dinner jacket swanking around in a sports car shooting at foreigners is the epitome of uncool, and even more so now that he has been bought by Amazon.

Trying too hard to be cool is also uncool, which is why, for all her attempts at sultriness, Victoria Beckham never makes the grade. You have to be relaxed to be cool: among news presenters, Jon Snow is cool and so is Clive Myrie but Krishnan Guru-Murthy is too nervy to be cool.

Coolness favours the laid-back, which is the cool way of saying lazy. That boring old slugabed Keith Richards is cool, whilst Mick Jagger, who has all the energy, is too hard-working to be cool. 

The same applies to Paul McCartney, who was always the most talented Beatle but never the coolest. No one in the Royal Family is cool, which is as it should be: whenever they try to be cool – dancing with locals, grooving with Rastas – they fall flat on their faces.

Politicians are rarely cool, though Barack Obama always was, and so, in his rumpled, unbothered way, is our own Ken Clarke. Being comfortable in your own skin is key.

Coolness can visit you late in life, once you have stopped being anxious or trying to impress. John Major, so awkward in high office, now seems as cool as a cucumber. But, then again, when were cucumbers ever cool?