about this time last year, crossing Paddington Station forecourt on our way to catch a train to Cornwall, my family and I were engulfed by a wave of men dressed as deckchairs.

That was what they looked like at first glance, anyway. And second glance, to be honest. But I finally figured it out: they were on their way to the Henley Regatta, and were wearing the striped blazers which are de rigueur for those who stand on the riverbank sculling Pimms instead of oars.

Now it takes a ton of chutzpah to carry off this look and I doubt if these gents could muster more than a couple of ounces of the stuff between them. But manoeuvering two nonplussed children through the crowd at least gave me the chance to observe them at close hand.

No two blazers were alike and most had vertical stripes in a variety of Willy Wonka-style candy colours. They were generally worn with a shirt and tie, cream or white chinos and finished off with brogues. There was the odd straw fedora and I think one or two of the younger dandies among them may have been in shorts and deck shoes. But I might be confusing that with a nightmare I had a couple of days later.

There were women in the group as well. No blazers here though, just bright dresses, hats and handbags. No culottes, shorts or trousers either, because they're banned. And everyone had what looked like a luggage label attached to their lapel. These determine how far into the inner sanctum you can go. If you're lucky, you might get as far as the Steward's Enclosure.

If I'd had to hand Jack Carlson and FE Castleberry's new coffee table book Rowing Blazers, I might even have been able to identify one or two of the club colours. Carlson is a former rower, Castleberry a photographer, and they've put together a study of some of the weirdest and more wonderful boating blazers out there, modelled by members of the respective clubs - the Goldie Boat Club, for instance, whose striped blazers are gold, British Racing Green and Cambridge Blue. Or the Undine Barge Club of Philadelphia, whose blazers are yellow, blue and white. As you've probably guessed, leafing through Rowing Blazers is a bit like looking at a Ralph Lauren catalogue. Only it's actually real.

"Like the court liveries and heraldic devices of medieval Europe, the street gang colours of Compton, and the patches and badges of Boy Scouts and Hell's Angels, rowing blazers are tribal totems," Carlson writes. "They are ceremonial vestments, worn to emphasize both community and difference: to impress, intimidate and influence in a game of sartorial one-upmanship."

I think that's a little OTT, though he hits the right note with the picture he draws of "unaware travellers" in Paddington Station who "imagine they must have stepped back in time, or into the dreamworld of PG Wodehouse." Yup, they certainly made me look twice. Mind you, I still think they looked like deckchairs.

Rowing Blazers by Jack Carlson with photography by FE Castleberry is published on by Thames & Hudson, priced £35, on July 7.