There is a confusing time period that occurs just after an interview with a famous person, during which both you and the famous person may be wandering around the corridors of the same building, and may therefore run into each other again. There is no approved etiquette for this meeting.

On the one hand, you have just been chatting together as if you were lifelong friends, so should you greet the famous person in the corridor with the same warm friendliness and pick up where your conversation left off? Or should you remember that you don’t know this person at all, that they were only speaking to you because it’s their job, and that people who don’t know them acting like they do know them is probably the principal irritant in their lives — and therefore nod, smile and walk quickly by?

Fortunately, Bobby Gillespie saves me from my social embarrassment. In fact, he marches straight over to me and actually says the single word “Embarrassment!”. How does he know? Does this swaggering rock front man suffer from the same moment of unease? No. It turns out that he’s talking about the Madness song of that name, espousing the merits of the band. If you were to compile a list of bands you thought Gillespie might admire, you’d probably include the Stooges, the MC5, the Rolling Stones and perhaps a few obscure krautrockers or little-known sonic experimentalists. But you wouldn’t mention Madness.

Then again, Gillespie and his band are full of surprises. Take their new album, Beautiful Future. After several years during which the band veered from noise terrorists to retro rockers, Beautiful Future unveils Primal Scream the pop group. We should have learnt to expect the unexpected from them by now: their very existence has confounded expectations. For many years, they were the epitome of drug-fuelled, “live fast, die young” rock’n’roll attitude. They should have imploded or exploded long ago; yet here they are, still a vibrant force 24 years on. Yes, there have been line-up changes, but the creative core of Gillespie and the guitarist Andrew Innes stretch back 20 years, and the relative new-boy bassist Gary “Mani” Mounfield has clocked up a dozen years. They even managed to survive the zeitgeist-defining success of their Screamadelica album. Often, when bands create an album that defines an era, the burden of expectation that follows only hastens their demise, as Mani — formerly of the Stone Roses — can attest.

I’m particularly pleased that Mani is here, because, as our interview begins, my first question is met with a snort of contempt by Gillespie, who slumps back into the sofa, physically disengaging himself from proceedings. This is slightly unsettling, because all I’ve done is wonder whether Beautiful Future’s upbeat music hides a darker lyrical message. Mani, in contrast to his singer, answers with cheerful good humour: “It’s another traditional Gillespie Trojan horse, isn’t it? A serious message imparted under a nice bubble-gummy pop tune.”

Some gentle coaxing brings Gillespie back into the conversation, and he explains his dislike of the question.

“I don’t really want to talk about the words of the songs, because I hate it when people explain what their songs are about,” he says. “I think everything in this culture is over-explained. So there’s no mystery. Part of the problem in music these days is that there’s no mystery. If there’s no mystery, you lose the power of the imagination. If I sat here and explained what the songs are about, I’d spoil it.

“Don’t get me wrong, the words are important. I have to believe what I’m singing, but if you’re in an art gallery, you don’t want the artist there explaining what the picture’s all about. You just want to let your imagination run riot. You shouldn’t isolate the lyrics. The lyrics, the music, the atmosphere, the energy all go together. The other thing I hate is bands who go on about what a hard time they had making their record.”

“It’s not a hard time, it’s a joyous time,” Mani says. “If this album sounds upbeat, it’s because we really enjoy each other’s company — and we’re not climbing up a ladder with a hod full of bricks. The job has its demands in other ways, but, hey, I’m doing what I always dreamt of doing.”

The pair of them begin to discuss Primal Scream’s innate chemistry, the magic that happens when they all play together and the moment when a song suddenly changes direction, not because any individual intends it to, but because the combined will of the band, Ouija-board-like, has sent it somewhere new. As an example, they mention Uptown, a song on the new album that began life as a fairly standard disco song but gradually took on its unique character — “Like Jah Wobble playing with Chic,” Mani says. As unlikely as that combination sounds, he’s pretty much nailed it.

“It’s a nonverbal thing in this band,” Gillespie says. “If you’ve got to explain it to somebody, perhaps they shouldn’t be in the band.” Mani concurs: “There’s definitely an ESP thing going on. You know where someone’s going before they go there.”

This chemistry is all the more impressive because, while Primal Scream is at its heart a traditional rock band, it often operates in a much looser way. Gillespie says that he drew inspiration from the way the funk pioneer George Clinton ran the bands Parliament and Funkadelic as ever-changing line-ups drawn from a collective of trusted musicians. Primal Scream stopped thinking like a band and started thinking like a producer, bringing in outside musicians as dictated by the song, and not worrying too much if one of the core band members wasn’t needed on a particular track.

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