I saw him — the loneliest man at Glastonbury. He was wearing a neon-green Hawaiian shirt, and he was next to a stall selling baguettes, and he was standing on a path facing a stage, and he was screaming that Jeremy Corbyn was a cunt.

This was not, actually, a stage that had Corbyn on it. His speech was being shown on the giant screens, yes, but only as a prelude to the Kaiser Chiefs. Possibly the man in the Hawaiian shirt didn’t know this. ‘You lost the election, you wanker!’ he shouted, and ‘Get the fuck out my life!’ and ‘IRA sympathiser!’ and ‘Hezbollah lover!’ and so on. He seemed, I thought, rather well informed. Despite being in the wrong place.

Most people pretended he wasn’t there. He was an embarrassment — a terrible, disfigured thing at which one did not wish to stare. One woman in a vest did ask some passing police to shut him up, it’s true, but they chuckled about free speech and refused. Instead she contented herself with standing next to him shouting ‘Corbyn is a hero!’ every time he shouted abuse, although that meant she couldn’t listen to the speech on the screens, which obviously bothered her. Perhaps, like me, she had tried to get to the Pyramid Stage, where the speech actually was, but had been defeated by the crowds, which were as treacle-thick that Saturday afternoon as they would be the following night for Ed Sheeran. The revellers at Glastonbury were mad keen on Jeremy Corbyn.

Mind you, a few years ago they were mad keen on pirates. Talking like them, dressing like them, all that. It was a real theme. All week, this time, I was hearing the new Jeremy Corbyn song — the ‘Oh, Jerrr-emy Corrrrrrbyn’ sung, beer-hall-style, to the tune of ‘Seven Nation Army’ by the White Stripes. Politically, that felt pretty ground-breaking. Did I hear it more, though, than I heard people say ‘Arrrrrrrrr!’ in 2007? Perhaps not.

On Friday night, while watching Radio-head, the chant seemed to take over that whole natural arena. ‘This is something big,’ I told myself, awestruck and perhaps a little alarmed. And yet the next night, Dave Grohl of the Foo Fighters got the same crowd to chant ‘fuck, fuck, fuck, fuck, fuck’ in a bid to beat Adele’s record for onstage profanity. Did the Glastonbury crowd love Jeremy Corbyn in the same way that they loved pirates and shouting ‘fuck’? Or in a completely different way? Honestly I do not know.

The speech was rubbish. Undeniably and objectively, rubbish is what it was. ‘There is only one planet,’ he shouted into his microphone, and ‘Not even Donald Trump believes there is another planet somewhere else!’ Except there are actually quite a few planets, aren’t there? This is well-known.

Honestly, the whole Corbyn thing still does my head in. I understand what his adoring fans believe he represents, but I’m buggered if I can figure out why they think he represents it. Why not do a better speech? Why not get some help, craft some uplifting lines, have a crack at immortality? Decades from now, researching now, historians will watch that speech, baffled, trying to figure out what the hell was going on. How, they will ask, did a man with nothing much to say and no talent for saying it manage to attract crowds like that? What did they all think they were getting out of it? Why did they decide he was the one?

Glastonbury matters. The very thought of it mattering sends some people into a sneering rage, but that doesn’t mean it doesn’t. Politically, despite long links with CND and union-based activism, it has never quite been a place of the hard left. There is a strong dash of West Country liberalism thrown into the mix, perhaps stemming from the Eavis family’s Methodist roots, which very much takes the edge off. Added to this, the festival also has an undeniable New Establishment vibe, very much aware of its own status as a British summer fixture, as much as Wimbledon or Ascot, albeit for people with different habits. Some attendees are just on a piss-up, certainly, but those who go back year after year consider Glastonbury festival attendance a core component of their identities. They have had a rough time lately.

John McDonnell doesn’t tap into that mindset. His anger, his condemnation; it’s hard to see it in fairy wings. A year ago, Corbyn couldn’t engage it, either. He was due to speak there in 2016, the day after the Brexit referendum, and pulled out at the last minute. Had he not done, he would have been heckled and despised because of his own vague equivocation during that debate. This time he was greeted as a hero. And that’s the shift, I think, that is worth noticing.

Is Britain at large more likely to vote Labour because 100,000 people in a field cheered a platitudinous speech by a man who was there to introduce the US hip-hop group Run The Jewels and in the end actually forgot to? Probably not. What Corbyn has done, though, is neutralise the threat from within. A year ago, the Glastonbury crowds were ripe for the taking. Had Labour moderates then had the bottle to split away and form something new, I really think it could have worked. Whereas now I fear it is too late to sell even the soft British left the promise of a Macron-style political revolution. It would be like trying to sell cowboy hats in pirate year. Look at them all. Listen to them all. They seem pretty sure they’re having a revolution already.