It was 40 years ago today (or, more exactly, next Friday), Sgt Pepper taught the band to play. Actually, old Sgt P did more than that: in 1967 he taught the rest of the world to listen in a way that it had never done before.

I was too young to remember the release of Sgt Pepper’s Lonely Hearts Club Band. The Summer of Love was, for me, the Summer of Toilet Training. Yet I do remember when I first heard the album. I was about ten years old when my father bought it and presented it to me, with the words: “This is fantastic.”

My father was musical, but he was not a fan of pop music. Indeed, he hated the stuff. He was an academic Oxford historian, and he knew a significant cultural artefact when he heard one. We spent that evening listening to it. My mind, to coin a phrase from the time, was blown, and so was his.

Sgt Pepper remains the most important album of all time (note: important, which is not the same as best). Several very dull books have been written about it. Every word and every note has been subjected to microscopic analysis. But I believe there are just two things that make the eighth Beatles album a cultural milestone: its astonishing artistic breadth, and its quintessential Britishness.

Thirteen songs recorded in a 700-hour burst of creativity, the album represented a deliberate decision by the band to turn its back on touring and the frenzy of Beatle-mania. For this, they invented an alter-ego band, and went in disguise, with ludicrous moustaches and elaborate costumes: an imaginary concert performance by a group that existed only in the band’s imagination.

As Shakespeare well knew, disguise offers freedom: unshackled from the constraints of performance, the band embraced an astonishing array of influences, and drugs. They would never work again in such harmony.

Here was a mould-breaking concept album, one of the first gatefold covers, and the first pop album to have the lyrics printed on the back. Hailing Sgt Pepperas the best rock’n’roll album ever, Rolling Stone magazine insisted that it “defined the revolutionary optimism of psychedelia and instantly spread the gospel of love, acid, Eastern spirituality and electric guitars around the globe.”

I didn’t know much about acid or psychedelic spirituality; I was simply enthralled by the inventiveness. I never cared whether, or how much, it was about drugs, since it was about so much else, and so ornately musical, an extravagant fantasy of rock, music-hall oompah, sitar, harpsichord, brass bands, fuzz guitar, full orchestra, crowd noise and barnyard sounds.

The combination of sentimentality, nostalgia and raw irony was, and remains, an expression of a particular sort of English cultural identity. The 4,000 holes could not have appeared anywhere but Blackburn, Lancashire; here is McCartney, going upstairs and having a smoke, puffing Woodbines (or whatever) on top of a double-decker school bus. “The English Army had just won the war”. What other kind of army could it possibly have been for Sgt Pepper and his troops, clad in their fabulous satin uniforms and wearing the MBE insignia presented to them by the Queen?

Lovely Rita, Mr Kite, Billy Shears, Henry the Horse, even Lucy (in the Sky with Diamonds): these are British figures, as embedded in our cultural landscape as any character from high literature. Like others, I remember feeling mildly offended that the grandchildren in When I’m Sixty Four should be named Vera, Chuck and Dave. Chuck? Later I discovered this is a Lancashire term of endearment, but it sounded American to me. What was wrong with Bert, or Alf?

Through it all ran a vein of self-mockery at the fakery (“You’re such a lovely audience, we’d like to take you home with us”) and the stock vaudeville fare that is “guaranteed to raise of smile”, tacky, enduring and ours.

Like all great cultural monuments, some spotted the significance, and some missed it completely. “A decisive moment in the history of Western civilisation,” wrote Kenneth Tynan, reviewing Sgt Pepper in The Times. “Dazzling but ultimately fraudulent,” thought Richard Goldstein, of The New York Times. Mae West initially balked at having her image on the cover (“What would I be doing in a lonely hearts club?”), but later relented and allowed herself to be immortalised, along with Freud, Wilde, Marlon Brando and Laurel and Hardy. The tough-guy actor Leo Gorcey demanded $500 for the use of his image, was removed from the cover, and is now almost entirely forgotten. Fame can be fickle – and that, in a way, was Sgt Pepper’s point.

Three years after the album was released, the Beatles broke up. But Sgt Pepper’s band played on, and on. The band we’ve known for all for these years. They really did want to take us home with them. And we are still there.

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