Mere minutes into our interview, and Pete Townshend is tucking in with the gusto that has stood him well these 70 years: to anecdotes, to philosophies, to past (and future) plans, to the plate of biscuits and pastries that has been placed in front of us in this drowsy Richmond hotel near his south-west London home.

Well, near one of his homes. And, given the musician owns seven recording studios, we’re probably also near more than one of those. His 15 boats? As we’re within rowing distance of the River Thames, we’re probably not far from some of that collection, too. “I’d like to say that I’m interested in model trains…” he will say. But no. Away from music, collecting studios and piloting boats are what Townshend does for relaxation.

“We used to come here every day for lunch,” says The Who’s brain trust, chomping on shortbread. “They did the most amazing sausage and mash. Rachel once had it every day for two weeks.” Rachel is Rachel Fuller, the songwriter/ guitarist/composer’s partner the past two decades. He met the now-41-year-old when he “employed her to do some orchestrations on the Lifehouse Chronicles,” he says of the 1990 box-set iteration of his abandoned 1970s rock opera.

Portrait by Denise Nestor (Denise Nestor)

The couple have worked together again on one of this summer’s Who-related projects: a classical rendering of his 1973 Mods and Rockers concept record-turned-film, Quadrophenia. It’s being released as an album on classical label Deutsche Grammophon – Lancastrian tenor Alfie Boe takes the place of Who singer Roger Daltrey – and performed at a one-off concert at London’s Royal Albert Hall.

Between album and concert comes another burst of Who action: the band is headlining the main Pyramid Stage on the final night of Glastonbury this month. Was it an immediate “yes” when the offer came through from Worthy Farm? “I don’t think it was an immediate yes from Roger,” Townshend replies. “I don’t really give a shit either way,” he adds, perhaps protesting a little too much. “But I think Roger was a little worried that we already had three shows in Europe lined up, and they were close together. Roger’s been needing quite long periods of days off in between shows.

“And there was doubt because it’s so high- profile – and, of course, it’s televised. So if you do goof, you goof big-time.” But with a little juggling of their schedule, Daltrey was reassured. “We’re playing great, so once he gave us the green light, we were good to go.”

Townshend performing in 1975 (Charlie Gillett Collections/Redferns)

Townshend also has a special interest in fellow headliner Kanye West: “I’ve never met him, but I’m about to as he has a business proposal for me. He makes a big play of the fact that he’s as much a businessman as an artist. But what he’s always been is a bit of a grown-up Grayson Perry – he’s very much a kind of installation guy… There’s this desire among R&B performers to create a mystique and sense of danger, but I imagine I’ll probably be disappointed that he’s quite normal.”

Before we can talk further about the ongoing vitality of a band currently celebrating their 50th anniversary with a world tour, Townshend is detouring through a grab-bag of reminiscences. There are quick-smart yarns about Soho in the 1960s; his musician father’s summer residencies on the Isle of Man; The Who’s 1968 gig at Paisley Ice Rink (“The ice was pink. It was full of blood!”); the 1975 Hollywood premiere of the film of Tommy; and his dalliances with Elton John. He starred – alongside Ann-Margret, Oliver Reed and Daltrey – in Ken Russell’s film about the pinball wizard and was then at the height of his herculean cocaine intake.

“Yeah, that’s right,” Townshend nods. “Well, I never did coke. Well,” he qualifies, “I did a couple of years of it – not like Elton, but I did a bit around him. And in 1980/81, I was hanging around the New Romantic scene, getting a bit depressed, marriage falling apart, ended up with a pretty blonde that I’d squire to nightclubs.

Sting in 1979’s 'Quadrophenia' (Rex Features)

“I was thinking about Steve Strange,” he motors on, now corralling the late Visage singer and New Romantic club promoter, “cos when he died recently I wanted to go to his funeral cos I really liked him. And I had an OD in his nightclub, Club For Heroes. I was with Paul Weller, and Phil whatsisname – not Oakey… Lynott,” he says, deciding on the late Thin Lizzy singer. “I think it was Phil Lynott who gave me the smack.” Did he snort it? “No, I injected it. In the toilets.”

This, disarmingly, head-spinningly, is Townshend all over. It’s all out there, on the table. A lifetime of fame (he was a teenager when The Who had their first hit, “I Can’t Explain”), thinking, overthinking, indulgence, spiritualism, addiction, sobriety and theorising can do that to a man. His autobiography, 2012’s Who I Am, was the same. Out it all poured. At one end, his theories on the post-war generation into which he was born; in too-simple brief, they weathered a brutal psychic hangover. At another, his mea culpa dissection of the circumstances surrounding his 2003 arrest on a charge of using his credit card to access a child pornography site.

Again, in too-too-simple brief: Townshend was testing what was out there, online, so he could confront the credit-card companies for being complicit in the abusive trade. He never viewed nor downloaded any images. And he was also trying to confront the childhood sexual trauma he thinks he suffered via his maternal grandmother. “I came up against abusers when I was young, and I’ve had to go into a place in my life where I’ve had to forgive them. And I’ve had to, in a way, say that what happened to me probably helped me in my career.” This is the carefully framed view now of the angry young man who wrote “My Generation”. “I can tap into the rage that I feel against them.”

Pop music: Good years and bad years Show all 6 1 /6 Pop music: Good years and bad years Pop music: Good years and bad years Good year: 1963 The breakthrough year for pop. The Beatles and The Beach Boys (pictured) released their debut albums three days and 5,000 miles apart, while Bob Dylan kick-started the folk boom with the single “Blowin’ In The Wind” and the album The Freewheelin’ Bob Dylan. Hulton Archive/Getty Images Pop music: Good years and bad years Bad year: 1960 It might not have been as bad were it not for what happened in 1958, when Elvis Presley was drafted into the US Army. He was replaced by prefabricated teen icons like Fabian, Pat Boone (pictured) and Frankie Avalon, and pop again became the province of Middle of the Road novelty pap. Hulton Archive/Getty Images Pop music: Good years and bad years Good year: 1975 The high watermark of pop’s diversity: stadium rock (Born To Run); stadium prog (Wish You Were Here); Krautrock (Neu!’s 75 and Kraftwerk’s Radio-Activity, pictured); confessional songwriting (Blood On The Tracks and Tonight’s The Night); proto-punk poetry (Patti Smith’s Horses); art-rock sophistication (Steely Dan’s Katy Lied and Joni Mitchell’s The Hissing Of Summer Lawns). AFP/Getty Images Pop music: Good years and bad years Bad year: 1985 Some measure of how bad the year was can be gleaned from knowing that of the year’s top 10 best-selling albums four were Now That’s What I Call Music and Hits compilations. Anthems abounded: “We Are The World”, “Shout” and “I Want To Know What Love Is” were the biggest singles, while album were dominated by Dire Straits’ Brothers In Arms and Phil Collins’ (pictured) No Jacket Required. AFP/Getty Images Pop music: Good years and bad years Good year: 1997 The last great heave of BritPop saw the mandatory No 1 albums for Blur and Oasis. But the genre was bursting at the seams, struggling to accommodate the huge success of Radiohead’s (pictured) neo-prog milestone OK Computer and the soundscaping innovations of The Prodigy and The Chemical Brothers. Hulton Archive/Getty Images Pop music: Good years and bad years Bad year: 2011 2011 really stands out for the cumulative impact of Cowellism, as the album charts were littered with the output of his telly talent shows, such deathless innovators as One Direction, Susan Boyle, JLS, Alfie Boe, Olly Murs (pictured), Joe McElderry, Matt Cardle, Rebecca Ferguson and Will Young. Getty Images

But, he acknowledges, while his arrest and the subsequent media storm, “was terrifying for a while…” He pauses, which is not something he does often, to weigh his words. “I think – it’s hard for me to say this – but I think it probably, in the long term, was a good thing for me. I mean,” he adds, snorting just a little, “the only thing that must be frustrating for those people who distribute gongs up in London, they probably want to give me a knighthood, but they can’t. And I don’t give a fuck,” he protests once more.

So, moving on: why another incarnation of Quadrophenia? It’s already been revived for a Who tour in 1996/97, and again in 2012/13, which begat a live album, released only last year.

Townshend’s reasoning is typically, ah, ambitious. “My idea was simply to make folios. There was a mate of mine who was in the Welsh Guards in the Falklands. And he said to me that we’ve got bombs – us, the Americans, the Russians, the Indians, the Chinese – which, if terrorists ever get hold of them, they will use them. And they’re flesh-eating – it’s like a magnetron bomb that kills everything that’s got flesh in it.”

Townshend amid rehearsals for the 'Quadrophenia' classical concert at the Royal Albert Hall

Bear with him; we’ll be at the Royal Albert Hall on a summer’s night in a second…

“And the subtext to it is that these bombs also erase data. So you would have this beautiful city full of dead people and no data, and you can move into it with your black flag, and establish a new caliphate with no difficulty whatsoever.

“So I just started to think, fuck, I want to make sure that several – maybe nine or 10 – what I call ‘grand rights’ music or dramatic pieces I’ve worked on over the years are on paper.”

In sum, then (it seems): when Isis secures Ramadi, overruns Baghdad and, say, takes k Brighton, Townshend wants to ensure his music endures. If he’s being satirical, he’s hiding it well.

Roger Daltrey and Townshend in the film of 'Tommy' (Rex Features)

So he hired the missus, had her orchestrate Quadrophenia, she made some demos, Deutsche Grammophon heard those, agreed to pay for an album recording, and suggested Boe. “I wasn’t really interested in making a record,” he shrugs. “I certainly wasn’t interested in trying to justify why I’d spent all this money on an orchestral thing to [mark] The Who’s 50th anniversary when I’m perfectly capable of making enough noise with my guitar! But it took on its own life.”

All this is part of a full slate for the man who recently passed the age at which his father died. Is he focused on using his time as keenly as possible? “Not quite that. But about 10 years ago I did the music for a little art film for my friend Peter Blake. And in the [accompanying] interview he said he wasn’t going to retire from painting, but he was going to retire from painting for money. I kinda take a leaf out of that book.

“I wouldn’t want to retire. My mind is sharp, I love doing what I’m doing. I was lucky to keep my hearing,” he notes. It’s a reference to difficulties that date back to an infamous and literally explosive antic from late Who drummer Keith Moon on the 1967 set of American TV show The Smothers Brothers Comedy Hour. “I’ve got a hearing system, which is expensive but worth it,” Townshend explains. “Anyway, my hearing is OK. And I’m looking at new stuff,” he says, adding that while he’s written “a lot of songs” that might constitute a new Who album, “to get 10 songs past Roger, you have to write 20. And I don’t know that I can keep that up.”

Townshend on stage in New York in 2013 (Getty Images)

There are, then, limits to his vigour, and his patience. And with original Who bass player John Entwistle having died in a Las Vegas hotel room in 2002, Townshend and Daltrey are the last men standing. Still, the band’s 50th anniversary celebrations roll on. There’s another “swing” through America after their summer engagements. And, come rain or mud – the conditions that attended their Pyramid Stage appearance in 2007 – The Who are determined to provide a rousing climax to Glastonbury 2015.

Townshend knows better than most what the event means. “In ’68 and ’69 we’d had the experience of Monterey, of the Isle of Wight, of Woodstock – and although they were all fucking dreadful for us, for me in particular,” he says with feeling, “when I walked away from them, I realised that the audience experience actually has very little to do with what happens on stage.”

Glastonbury especially, he acknowledges, “has this legacy, this variation and texture” that other rock festivals don’t. “And I’m looking forward to my part. But it is just a small part. It would be wrong to call The Who the icing on the cake…” He grapples for a second for an appropriate Brit rockfest metaphor. Presently, it comes. “We’re the steam on the poo!”