But the three-minute single blueprint proved too restrictive and, in 1969, Manfred moved from his pop straitjacket to one of his own devising in the short-lived Chapter Three. Formed with ever-present drummer Mike Hugg, it was "a conscious decision to turn our back on what we'd been doing, but we had too many anti-pop rules: no guitar, we had to only write our own songs." Two jazzy and determinedly uncommercial albums resulted, plus an unreleased effort shortly to be represented on a box set.

Chapter Three's frustrations during their brief life led to a new project – the Earthband – where the only rule was that there were no rules. "Chapter Three was very specific, so we said let's just play and see what happens." The first long-player from Manfred, Mick Rogers, Chris Slade and Colin Pattenden arrived in 1972, the first of three Top 10 hit singles, 'Joybringer', a year later, and the story continues successfully today, albeit with a new line-up. "It's a constantly evolving thing, a series of different people in different situations. I just want it to be right." Current lead vocalist Noel McCalla follows in the celebrated footsteps of Chris Thompson and Mick Rogers, the latter having returned to the ever-changing ranks.

The Earthband's commercial peak came in 1976 when 'Blinded By The Light' topped the US chart. Perversely, perhaps, Manfred took the decision to withdraw from that most lucrative of music markets. "We went round America for six weeks, with me not seeing my children, and came back with $1500 dollars in my pocket - on a Number 1 record! We didn't break the market, just had one big hit. So we were never really famous in America."

He rejects the suggestion he turned his back on success. "I haven't had so much success in my life that I can run from it! With the Earthband, that is – certainly in the 1960s I wanted to run sometimes! But that was fame. That was being recognised in the street, that was different from success."

And if we're talking purely musically, Manfred undoubtedly has the Midas touch. As with Bruce Springsteen's 'Blinded By The Light', he's successfully brought his interpretative powers to bear on material by Bob Marley, Sting, Paul Weller, Del Amitri's Justin Currie and others. "Jazz musicians do other people's songs all the time, so for me it was quite natural." He's open enough, too, to participate in a Funkstar Deluxe re-recording of 'Blinded' which became a European hit late in 2002, following in the successful footsteps of Bob Marley's 'The Sun Is Shining'. (The video is the final track on the 'Evolution Of Mann' DVD.) Far from enshrining his history in stone, Manfred Mann is happy to take risks in the cause of progress.

1991 brought a masterpiece in 'Plains Music' reflecting the music and culture of the North American Indian. He rates it "the only thing I can listen to that's reasonably natural, not trying to be anything. The other stuff I keep hearing how I should have done it differently!" Ever the perfectionist, he can most often be found in his Workhouse studio on London's Old Kent Road planning his latest musical enterprise.

In an era when classic rock and its practitioners is finally being given its due, Manfred has no plans to hang up his keyboard. "Count Basie rocked till he dropped, Beethoven rocked till he dropped, Frank Sinatra, Ella Fitzgerald…it doesn't seem that odd that people should play music for their lives, if that's what they do. Pop, rock and jazz is the music of the 20th century, certainly the last half, and the best music will last. I started off being a musician and I'm carrying on being a musician. As long as people will pay to see us do gigs, I'll perform."

From that, we can safely conclude that Mann-made music is set to reverberate for some while yet. The evolution is far from complete – and fans will be more than happy about that.