The fact that Ed Sheeran was a triumph at last weekend’s Pyramid Stage at Glastonbury 2017, armed with little more than a guitar, will have irked many people.

Sheeran is pop Marmite, insomuch as many adore him and others make terrific retching noises at his name and behave like you’re trying to poison them. Pre-Glastonbury, many quibbled that Sheeran was not Pyramid Stage material, whatever that means. I remember distinctly that Beyoncé was not supposed to be Pyramid Stage material either. Or, for that matter, Dolly Parton or Shirley Bassey. In fact, as far as I can see, any musical acts that don’t consist of four or five white men rocking out with songs about things like “open highways” will be cited over the months leading up to the festival as chancing imposters here to ruin everything.

Sheeran possibly copped the Glasto-flak more than most as, well, he’s Ed Sheeran: phenomenally globally successful, richer than God, friend of the stars, purveyor of endlessly playlisted pop and, more recently, the singer of “Galway Girl”. Sheeran’s latest smash hit is up-tempo folky eardrum knotweed. If you were on the fence about Sheeran, “Galway Girl” will have shook you off, possibly into a steaming cowpat. “Galway Girl” is a huge, delightfully daft, pseudo-fiddle-dee-dee stomper where Sheeran describes pulling a maverick-sounding woman in Dublin and going on to have the best impromptu night of his life. “What is this horrible noise? I don’t believe this is really a song. It is hideous!” flashed a message on my phone on Sunday night. “Ah, that will be ‘Galway Girl’ starting,” I thought. Once heard, never forgotten.

An entry point to understanding why Sheeran can intoxicate large crowds, both at Glastonbury and across the world, it’s a tune that holds many of the answers. Sheeran’s record company reportedly begged him not to put it on his last album due to its deep uncoolness. It was the opposite of what they felt modern audiences liked. But they were wrong and he was right. Because yes, it sounds like something Father Ted and Father Dermot might have written after “My Lovely Horse”. Yes, it rhymes “fiddle in an Irish band” with “fell in love with an English man”. Yes, it’s performed by an average-looking lad in clothes that often feel like he picked them out of an Ali Baba washing basket, sniffed, and said: “OK, one more day.”

But “Galway Girl”, like so many of Sheeran’s songs, is full of relatable notions such as playing drunken darts as a flirting device and sticking Van Morrison on the jukebox. It’s about snogging furiously while tipsy and winding up in a strange flat eating Doritos. “Galway Girl” is a song about falling instantly, deeply in love, which of course is lust. As a song, it speaks to any man who ever got lucky on a stag night to Dublin, or any girl who ever drank too much prosecco on a Friday and wound up with a love-bite in a karaoke bar from someone on a sports tour called Dermot.

Much of Sheeran’s appeal is that his music skewers the mood of being youthful. Not merely being youthful now, but recalling one’s youth. His themes are ageless. “Thinking out Loud” is about finding a lifelong love that will stick around when you’re white-haired and immobile. It is three minutes of sappy, schmaltzy, painfully hopeful, old-fashioned, beautifully hewn pop cheese that can have me in tears in a 3am minicab before it reaches the first chorus. Millions sang along to it on Sunday evening. Millions of people didn’t care if they were uncool.

Sheeran is rarely political. Or preachy. He doesn’t present a jet-set, Instagram-perfect, “No Carbs Till Marbs” view of life. His songs are mainly about love: finding it, being surprised by it, losing it, mourning it. I like his tendency to see relationships as a sort of wonderful temporary mental illness, shadowing everything, ruining all calm. “Shape of You”, another heavily rotated song that irks the painfully cool, is gloriously accurate on the idiocy of new love. Sheeran sings of being wholly preoccupied by having bedsheets that smell of his new girlfriend’s perfume. He describes being so newly smitten all one can do is paw their skin and ride a big dipper of emotions.

“Ugh, but imagine doing it with him!” is a typical riposte, because he’s so fabulously everyday-looking. But when we attack Sheeran’s looks, his red hair, his impish face, his realness, we expose ourselves as people who have forgotten, or are wilfully blind, to how the unfiltered world is. Millions of everyday people have a hero in Sheeran. If he isn’t Pyramid Stage material, he didn’t get the memo.

The Independent