The Prince and Princess of Wales sent a congratulatory video message at the end of the Olympics – but that wasn’t all that people noticed.

For once, it also wasn’t the wellbeing of Catherine that was under scrutiny.

Instead, it was Prince William’s holiday beard.

Royal fans immediately began asking: was this going to be a permanent feature? Or was the beard an outbreak of summer bohemianism that hits middle-aged men on their holidays?

You know what it’s like – they start thinking it’s Glasto in the 1990s.

It begins with the socks disappearing, then moves onto that creative T-shirt, or the collarless linen shirt, and then the shades that looked cool in the reflection of the third bottle of wine.

But if this proves more than a fleeting moment of royal stubble, it wouldn’t be the first royal beard.

It might now be a case of God Shave the King, but when Charles was a young man in the navy in the 1970s he sported an impressive beard. It was a kind of gamekeeper chic.

Although all Windsors with beards run the risk of looking like Russian tsars.

Prince William’s brother Harry has also been a prominent beard-wearer. Although whatever you say, don’t mix up hair with heir.

The issue of beards came up in Prince Harry’s book Spare.

“To beard or not to beard, that was the question,” wrote Harry, as he remembered how his grandfather Prince Philip wanted more beard rather than less.

“Let grow the luxurious bristles of a bloody Viking!” he wrote.

The beard was also a source of contention between the brothers, according to Prince Harry’s book, with Harry wanting to have a beard at his wedding to Meghan, while he claimed Prince William thought he shouldn’t.

Perhaps what is most intriguing, though, is how Harry’s beard took on a symbolic importance for him, as something that put a check on his anxiety and helped him “quell my nerves”.

“I couldn’t explain it, though I did find articles describing the phenomenon. Maybe it was Freudian – beard as security blanket. Maybe it was Jungian – beard as mask. Whatever, it made me calmer…” wrote Prince Harry.

Whether or not Prince William has taken criticism of his beard on the chin, it seems to have gone down well with his royal fans.

The New York Post’s Page Six, the paper of record for such moments, summed it up as “Wowza.”

However, there was a more cautious approach from the Beard Liberation Front, a group that campaigns in support of beards.

Spokesman and prominent letter writer Keith Flett says the group is “continuing to review Prince William’s latest beard and assessing if it is contributing to a positive image of the hirsute in the public eye”.

I suppose they are razor-sharp critics in such an organisation.

But the royal beard proved to be the talking point at the end of the Olympics, even overshadowing the appearance of Tom Cruise, who was seen travelling by motorbike, plane and parachute.

Prince William has already been something of a royal style pioneer, pushing ahead with the tie-less monarchy.

There’s often a casual, relaxed style on his visits, which is useful for putting people at ease.

It’s the dad at the school barbecue look. Although – apologies in advance – he’ll now be avoiding the barber queue.

William represents a millennial version of the monarchy and on visits he has the style of a generation that’s used to working from home. Or palace in his case.

It’s the depths of summer now though. So there’s no need to bristle and plenty of ways of keeping up to scratch.