Any keen student of that magical era for British Pop, the early-mid 1960s, will find one name cropping up time and again - Welsh singer and guitarist, Spencer Davis. The Spencer Davis Group had ten hit singles during a golden spell and at least three of them are constantly played on radio today - the band's theme, song "Keep On Running" with the definitive Muff Winwood bass line, "Gimme Some Lovin" and the sublime "I'm A Man".

On its own that would be sufficient to win Spencer and his band a place in music history, but our keen student will also have spotted that the man's influence was considerably greater than even those era-defining hits. Read anything about the London club scene of the period and who's that pictured with John Lennon and Paul McCartney? Ah yes, Spencer Davis. And who's that jamming with Charlie Watts? It's that man again. Spencer was the coolest of the cool at the time, hung out with everyone and is one of the few not only to have survived, but survived with his marbles intact.

These days, Spencer Davis lives in the USA, to which he emigrated in 1970 - California, specifically, a base from which he still tours, playing his mix of Blues, Folk-Blues and Rock - recently in New Zealand as part of the British Lions Rugby tour and currently, on an extensive tour of Germany.

There is another interesting feature of TSDG - when the band first appeared in 1963 it featured the impossibly young Steve Winwood on vocal and keyboards, sounding like a young Ray Charles. What became of Steve Winwood, you almost certainly know, but significantly, everyone in the band went on to good things, too. Steve's brother, Muff became a major figure in record label A&R and the band's drummer, Pete York, has been a name in the drumming world ever since.

As the tea brewed (you can't separate a true Welshman from his tea - even in California!) the talk tended to ramble. Here is a man with enough anecdotes to fill a season of Parkinson shows but, curiously, that doesn't necessarily make for an easy interview. It's easy to lose direction. What this man must do - and the music world needs it badly - is sit down and write his autobiography.

Back at the beginning, Spencer Davis's career path could hardly have seemed much further from Rock and Roll. Gifted with languages, he studied comparative philology at university in Birmingham (he's fluent in German, French, Swedish, Dutch and Spanish, let alone English) and played in a Blues band at the weekends.

'I was supposed to have become an academic, but that all went out of the window when I put the band together with Muff, Pete and the very young Steve Winwood.'

There are numerous versions of the legend telling how Spencer first found Steve Winwood, so I asked if we could, at last, hear the version from, as it were, the horse's mouth.

'I first saw Steve playing piano in a pub in Birmingham, in Erdington. He was sitting there, playing like Oscar Peterson and singing like Ray Charles. I thought, this guy is too good to be true - he's two for the price of one and I'm having him in the band, now! His brother, Muff, came along, switched from guitar to bass and that was that'.

At the time, Spencer was a schoolteacher and Winwood was only 15, but despite the age gap, the band was formed, turned professional, was signed by the hugely influential manager, Chris Blackwell and found itself signed to the Fontana label.

'At the end of '63 we did some early singles, including a cover of John Lee Hooker's "Dimples". We had a few other singles out too, and they nibbled at the Top 20, "Every Little Bit Hurts", "I Can't Stand It" and they all featured Steve's wonderful ability to mimic Ray Charles,' he says.

'You know, Steve reminds me of Peter Sellers, who had that wonderful ability to imitate people. But just like we never got to know the real Peter Sellers, because he was always being some other character, Steve was like that, too. He's like a musical sponge, he can absorb someone's style. At 16, he suddenly became an old black Blues singer and he was quite phenomenal. He could pick up any instrument, literally any instrument, get something out of it and eventually master it. He was really amazing'.

In 1966, the band hit the big time with their first No 1, "Keep On Running". At the time they were one of the hottest R&B outfits (in the original sense of the term) in the UK - no one had a voice like Steve Winwood's and few could match the band's energy.

But already there were differences. As success followed success, Steve Winwood started to develop as a songwriter and wanted to work with other musicians. In 1967 he left the band, to form Traffic, strongly supported by the aforementioned Chris Blackwell. Spencer says that taught him a distinct lesson about how the music business operates.

'Yes - the Davis family motto, "Slow to learn, quick to forget"' he says, ruefully. 'A lot of people had written me off in the UK because they said once Steve Winwood left, well, he was the Spencer Davis group. But how could that be? On one occasion, Steve was sick with laryngitis and we were playing for a boxing promoter in the East End of London. John Glover, who ended up managing Victoria Beckham and others, but who was then our road manager, said we couldn't do the gig without Steve. But we did it anyway - we got Dave Mason in and we were fine.

'But that was the moment when the light went on in Blackwell's head. He was at the gig and he realised, after seeing how well we played without Steve, that that he could have the Spencer Davis Group and Steve Winwood.'

After a brief spell with new members in the band but no more hits, Spencer decided it was time to go solo, too, and get back to his own roots in the Blues.

'You know, when the whole thing unravels, the best thing to do is go back to the beginning and start all over again and that's exactly what I did. I went back to the Folk and Blues clubs around Britain, booked by Acker Bilk's Brother, who was an agent - the Bilk Marketing Board they called them!'

By rights, at this stage of his career, Spencer Davis should have been a very rich man indeed. The band had toured incessantly for several years and had had hit singles right around the world. But this was in the 1960s and if the music business today has a questionable reputation for straight dealing, back then almost everyone was getting royally screwed by the business side of the business,

It's clear from the tone of his voice, that Spencer Davis's feelings about Chris Blackwell, the legendary head of Island records, TSDG aren't what you might call particularly fond.

'I didn't realise what had been going on. I'd sold millions of records and hadn't seen a penny from them. In fact the first I ever saw of it was when I was leaving to emigrate to the USA, in 1970. I was considering declaring bankruptcy, but I'd written a track with Eddie Hardin, called "Don't Want You No More", which the Allman Brothers put on their Beginnings album. The damned thing sold six million copies. Suddenly a cheque for £5,000 arrived through the door and I'd never seen so much money in all my life. I saw more money from that one song than I saw from all the stuff that had been an Island production. Management was essentially taking 50 per cent, the other 50 per cent was divided four ways, plus another 25 per cent take off that again.'

The conversation rolls on with some astonishing revelations about behind the scenes cash deals, which Spencer alleges took place and which British libel laws make it unwise to print. Suffice it to say that they do nothing but reinforce the impression that the music industry was (is?) the biggest shark pond this side of the South China Sea and that any musician who gets involved without having a rottweiler of a lawyer on her or his side is, to put it bluntly, a fool.

'I don't have any regrets or sour grapes. I just went off on my own and just forged ahead like a Welsh whippet, but it still goes on. Whenever someone says to you, "You're the artist, you take care of the music and I'll take care of the business", that's when the red flag should go up. Always have representation and make sure that representation has no conflict. With us, Chris Blackwell was our manager, our agent, our record producer, our music publishing company and more.'

Following the demise of that first incarnation of the band, while Spencer may have seemed to have dropped off the UK's radar, he was, in fact, doing huge business in Germany. But in 1970 he was offered what he describes as 'a very lucrative contract' and moved to the USA.

'Part of the condition for that contract, was that I had to take up residence here and it was the best move I ever made. I went over as an artist, made two albums that are now hard to find - "It's Been So Long" and "Mousetrap" and I've never looked back.'

Though massive success has eluded him, he has toured incessantly and worked with some of the greatest names in Rock, including Brian Auger, Chris Farlowe and even The Grateful Dead. Recently, he has been working in a band with Mitch Ryder, Chuck Negron and Rick Derringer.

The current project, in between tours, is a new CD (the release of which has still to be scheduled). 'It's very autobiographical - it's called "So far", meaning where we are now - a good ride, so far. It's got 12 tracks and I've got one more left to do.'

What label should we look out for?

'No, no... I am the label now. I've been down that road so many times before. I own most of my CDs now, acquiring the rights back on things. So that's my recommendation in answer to your question about your readers who might be starting out today. Kids will see the manager driving the Porsche and assume he must be doing something right, because he's driving such a great car. Of course he's driving such a great car - he's using your bloody money to pay for it! That's how so many of these people operate.'

After some lean years, things are starting to look good again for Spencer Davis. Ask him why and he says, 'I don't know - maybe it's a process of elimination? So many of my generation are no longer around. Drugs, a lot of them. People ask me if I have a drugs problem - I do. I can't afford them!'

The conversation turned to guitars won and lost down the years - and this is a man who has owned a lot of guitars in his time.

'Yeah, I sold the Gibson Les Paul that I bought from Tony Hicks of the Hollies for £500, patted myself on the back because I'd doubled my money and now that guitar today is worth $240,000 - and I don't have it! Mind you, I have two Zemaitis guitars and a National steel and a few others,' he laughs.

Would he class himself as a collector?

'More a guitar lover,' he says. 'I do have quite a collection - some amazing guitars - but I don't go out of my way to collect them, but when people call me up and ask if I'm interested in seeing something, I'm always interested - I love guitars'

And then he slyly announces: 'You know, I've got your guitar...'

Forgive the personal note here, but it explains why Mr Davis is shown holding a guitar with my name on in the accompanying picture - except it's not really my name, it's that Hollywood actor after whom I was not (my mother insists) named. It's just one of many instruments Spencer has collected down the years - and just one of the thousands of stories he can keep you enthralled with. 'I paid $500 for it in 1971 or '72,' he laughs.

With no immediate plans to visit the UK again (he was last here with a reformed SDG in 2004), we'll just have to wait for the CD. And that autobiography. It'll make fascinating reading!

Ends.