It is 10pm on May Day, and just as the polling stations are closing, Paul Weller leans conspiratorially across the restaurant table. "I'm going to play 'Eton Rifles' tomorrow night," he whispers with a hint of pride. "The time is right again, don't you think?" As we talk at a quiet trattoria in a central London side street, a Boris Johnson victory is looking inevitable. "I thought I'd never play that song again, but it's just as powerful now, just as relevant, as it was in 1979."
"That song" was written after Weller, aged 21, saw a TV report about Right to Work marchers being jeered by the schoolboys as they passed the gates of Eton College en route from Liverpool to London. "The Eton Rifles" is, like much of his work with the Jam, a satire railing against inequality and social division. Over a seething backdrop of rumbling drums and squalling feedback, a three-minute class war is played out, riven with resignation - "What chance have you got against a tie and a crest?" - and sarcasm: "We were no match for their untamed wit."
Three decades later, the young chaps dressed in Eton's black tailcoats and white ties when that song came out are becoming some of the most powerful politicians in Britain. They clearly didn't respond to the music of their youth in quite the way the musicians intended: Mayor Johnson has a well-publicised taste for the Clash, particularly their 1980 Sandinista! album. And the Conservative Party leader, David Cameron, recently told a Radio 4 programme, The Jam Generation, that his favourite song was "'The Eton Rifles', inevitably. I was one, in the corps. It meant a lot, some of those early Jam albums we used to listen to. I don't see why the left should be the only ones allowed to listen to protest songs."
The man who wrote the song shakes his head with disbelief. "Which part of it didn't he get? It wasn't intended as a fucking jolly drinking song for the cadet corps. I'll play that tomorrow night with as much passion as when it was written nearly 30 years ago. It's never been more appropriate, man." Weller celebrates his 50th birthday this month, and the day after our interview he played the first date of a nationwide tour to promote a new album, 22 Dreams. It's a long way from his first gig as a 14-year-old schoolboy at the Walton Road Working Men's Club in Woking in 1972, but the nerves haven't gone away. "I'll be terrified. Half an hour before I go on I'll be locked away, alone, very quiet. I'll be reflecting on what I need to do, on whether I can still do it. I'll be wishing I was anywhere in the world but that dressing room at that moment, you know, knotted and sick with nerves. It never gets any easier."
"The Eton Rifles" is the only hit from Weller's back catalogue that he plans to include in the set. His artistic sights are set firmly forward, and while he still rails against Boris and Cameron, he grew disenchanted with political activism long ago. A photograph of the 1985 press conference that launched the pro-Labour pop collective Red Wedge captures a moustachioed Ken Livingstone with one arm around the shoulder of Neil Kinnock and the other embracing Paul Weller, who was then playing with the Style Council. He is wearing a scarlet V-neck sweater over a white polo neck, and looks as if he is seeking assurance from Billy Bragg, who stands (both physically and philosophically) to Kinnock's left.
Today, however, he admits that he hasn't voted in the local elections. "I really didn't know who to vote for. I threw my polling card in the bin. Obviously I'd vote tactically if it meant keeping the BNP or some other nutter out. But Ken or Boris? What choice is that?"
I remind him that he once stood shoulder to shoulder with the soon-to-be-ousted mayor, comrades united by anti-Thatcherism. "Yes, but power corrupts. He's just become another professional politician, looking out for himself. Bendy buses! And Boris. How can you vote for a man who looks like he's got his mum to cut his hair with the garden shears? He's a gibbering idiot, like Tim Nice But Dim." He doesn't buy the idea that Johnson's cuddly-fool demeanour may be an act. "Then he's a fucking good actor, mate."
While the younger Weller bemoaned the 1970s Tory resurgence in song ("The braying sheep on my TV screen/Make this boys shout, make this boy scream!"), the middle-aged version draws inspiration from his five children and from God. "Yes, I'm a believer," he says, "not in a structured Christian sense, but you can either be open to all possibilities beyond physical existence, or you can shut it out. And how on earth can denial be a positive way to advance or enhance your life? So, yes, I sort of pray. I have a quiet word now and then." 22 Dreams is underpinned by this tentative spirituality. "I'm well aware that you're only as good as your latest work, but I'm quite happy for anyone to judge me by 22 Dreams," he says, adding with a rare flash of the old arrogance: "It's one of the best things I've ever done."
It is certainly bold. A 24-song double album, 22 Dreams incorporates virtually every musical influence that has been brought to bear on Weller's career so far. It opens with folk fiddling and Bert Jansch-style raga guitar work and, with a blast of soul horns and furious drumming, crash straight into the title track ("Had 22 dreams last night and you were in 21/The last one I saved for myself"). Weller himself plays drums on the yearning soul of "Empty Ring". Robert Wyatt blows a mournful jazz trumpet to interrupt the loping groove of "Song for Alice", a tribute to the late Alice Coltrane; the former Blur guitarist Graham Coxon takes to the drums on the woozy, bucolic "Black River"; Noel Gallagher gets on bass for the pounding, psychedelic rock of "Echoes Round the Sun". Elsewhere, a piano-playing Weller leads a string quartet in a lullaby for the youngest of his five kids, croons his way through a tango, and offers a pained piano ballad in the stark and delicate "Invisible".
Weller regards the LP as an early birthday present to himself. "It's totally self-indulgent - it's the record I wanted to make, had to make." He originally intended to call the album "Gather Ye Rosebuds While Ye May", after a John Waterhouse pre-Raphaelite painting of the same name. Recorded over the course of a year in his own Black Barn Studios, hidden down a rutted track in the fields that surround the picturesque Surrey village of Ripley, the album is also a product of its environment. "The barn plays a key role on the record," explains Weller. "I like recording with the doors wide open, whatever the weather. We watched the seasons change whilst we were making music, and I've tried to convey that sense of life coming full circle. So, in a way, it's a kind of concept album."
His voice tails off and he becomes guarded, seemingly wary of himself. Weller does this whenever the conversation veers too close to artistic hows and whys, to motivations and meanings. "Without sounding too poncey about it . . ." is a phrase he uses to precede any analysis of his artistic output. "I would like people to listen to this record in one sitting," he says, "to follow the journey. Stick with it. It's a good trip."
Paul Weller's nationwide tour continues until 23 May. For more information log on to: www.paulweller.com 
"22 Dreams" (Universal) is released on 2 June
Paul Weller: The CV
- 25 May 1958 John William Weller is born in Sheerwater, near Woking. His mother, a cleaner, and his father, a builder, later rename him Paul
- 1970 Paul is given a guitar by his family, and after a few initial lessons teaches himself how to play
- 1973 Performs his first gig at the Walton Road Working Men's Club in Woking with his friend Steve Brookes, with whom he then forms the Jam
- 1977 The Jam sign to Polydor Records for £6,000. Later that year they perform on Top of the Pops
- 1980 The Jam have their first number one single with "Going Underground"
- 1983 Weller forms the Style Council with friends. The band's first album, Introducing the Style Council, is released
- 1984 The Style Council perform on the Band Aid record "Do They Know It's Christmas?"
- 1989 Weller disbands the Style Council after their record company refuses to release their fifth album, Modernism: a New Decade. Weller takes a two-year break
- 1991 Returns as the Paul Weller Movement. He will later be known simply by his name
- 1995 The release of Stanley Road, named after the Woking street in which he grew up. It becomes the best-selling album of his career
- 2006 Release of Hit Parade - a compilation of singles from throughout Weller's career. The same year, he declines a CBE in the Queen's Birthday Honours List