Last weekend, in a pleasant park outside Maidstone, a most unusual rock festival took place. For one thing, it was a rock festival. Despite ‘rock festival’ being a common term for any live music event featuring multiple artists taking place outdoors, there are very few actual rock festivals any more. There are festivals for specific forms of rock — the metal events Download and Bloodstock — and there are festivals that have a few rock bands amid everything else. But not festivals that feature a broad range of bands, all of whom can be called ‘rock’ — hard rock, prog rock, country rock, blues rock.

For another, there was the crowd. There were no gangs of shirtless teenaged boys, overly exuberant at being out in a place where the normal rules of social engagement don’t apply. There were no groups of young women, faces painted with glitter. There were some small kids, some twenty- and thirty-somethings, but they were outnumbered by the swarms of the middle aged, buzzing idly — and in an orderly fashion — around the site, most of them, by far, being men. How middle aged? Never have I seen so much garden furniture at a music festival: it was like a branch of B&Q on the year’s first hot day.

‘Broadly, our crowd is middle aged, white,’ says the director of Ramblin’ Man Fair, Chris Ingham. ‘Some are empty nesters. Some bring grandkids. They like to enjoy themselves but they pace themselves. They police themselves — we haven’t had one arrest in five years.’

The nearest thing I saw to rebellion was a tipsy man throwing his plastic pint glass to the floor (which his wife picked up and put in a bin). Astonishingly, while I was at the front of the main stage, watching the vintage American band Cheap Trick, a festival worker with a bin bag and a litter picker worked his way through the crowd.

‘Thing is,’ said a festival-goer who claimed to be called King Zeus III, from Rigel 5 (his friends addressed him as Gavin, and he spoke with a Yorkshire accent), ‘I don’t want to go to a festival to be surrounded by kids. I want one that’s age appropriate.’ I asked if he was familiar with the concept of the ‘safe space’. One of King Zeus III’s friends butted in. ‘My daughter’s always talking about safe spaces. That’s what this is. This is a safe space for people like us. No one is being bolshy. No one is too pissed. There’s a bit of weed, but I can’t see any pilled-up arseholes, can you?’

Ramblin’ Man Fair isn’t the only festival that targets an older crowd. So-called ‘boutique’ events such as End of the Road and Green Man do so too. But they don’t target the middle aged to the virtual exclusion of everyone else. Unlike other festivals, Ramblin’ Man doesn’t have a kids’ area (though it did, for reasons I am not clear about, have an encampment of American Civil War reenactors right in the middle of the site, between two stages); it does not feature any of the kind of artists who get tipped as ones to watch in national newspapers (among its new bands were the Allman Betts Band, who get round the issue of Gregg Allman being dead by being led by his son); its merchandise, aimed at those for whom fashionable design is not top of their list of priorities, includes an official Ramblin’ Man Hawaiian shirt.

And all of that makes perfect sense. The middle aged are the people who have money to spend, and are willing to spend it. When the young band Ryders Creed, who sound exactly like the 1976, announce they have run out of CDs to sell, there is an audible groan; this is the age group that still buys CDs. And festivals are one of the places where people will spend a lot of money. The music industry umbrella body UK Music estimated that ‘music tourists’ — those travelling specifically to watch music — spent a total of £2.5 billion on festival attendance in 2016, the last year for which figures are available.

It makes sense, too, to return the festival to its rock roots. For all its current unfashionability, rock music — by which I mean the heavier end, where hair is long and solos longer — supports two newsstand magazines (Classic Rock and Planet Rock, a festival sponsor), and two national radio stations (Absolute Classic Rock and, again, Planet Rock). The people are out there, but the obsession with the new, the novel, the hip has marginalised them.

There had been events for the older rock fan before, Chris Ingham says, but they were the indoor festivals in off-season holiday camps. ‘But British people want to go outdoors. That’s part of our national culture. That space was chronically underserved. No one thinks about passion enduring into later stages of life. But people over 40 have passion too.’