Giles Smith didn't want to be just any old rock star. He wanted to be Sting. But his Eighties pop group, The Cleaners from Venus, let him down badly. All seemed lost, until, one fine day, the phone rang... 

Word came through from the man at A&M Records; Sting fancied a jam. Any interest? I'm used to this, obviously. Given my history as former keyboards man with the legendary late-Eighties UK pop combo, the Cleaners from Venus (two albums, one tour of Germany, no hits and a messy inter-personal combustion), international rock stars are at one at me on virtually a daily basis to come out of retirement and play with them. "Oh, go on, just for an hour," they say, but I smile and say, quietly but firmly, "That's all in the past now." 

In Sting's case, though, maybe I would make an exception. I have written a book called Lost in Music. It is the story, chiefly, of the Cleaners from Venus's baffling failure to go global coupled with some thoughts about why I - and a billion other differently talented adolescent musicians - devoted unconscionable amounts of time, energy and money to the unlikely project of becoming a rock star. 

In the course of all this the book confesses explicitly to some fantasies I have had, over the years, about Sting - specifically about wanting his job. It occurred to me early on, that if one had to be a rock star (and for a long time I thought I did) Sting would be a pretty good one to be. There are plenty of decent musical reasons for wishing to be Sting, who has amassed a back catalogue of cracking pop records, but there are also extra-musical ones. 

Like the fact that he looks great (and younger, I would say in the flesh than in photographs, which is an unusual trick). He is also what you might call comfortably off. Last year, during the court case in which Sting's accountant was successfully prosecuted for embezzlement, it emerged that £6 million had slipped out of Sting's bank account without him knowing. That's my kind of bank account. In short, I was on for Sting's lifestyle - at least as I imagined it from the outside. I mean how hard could it be? "What does Sting actually do," I asked in the book, "when he isn't touring or making records? He mucks about I reckon." 

Sting may have had his own tactics for asking me on board for an afternoon. He hasn't had a multi-million-selling album since his last one. Everyone can use a little fresh blood and a different perspective. As for me - well, perhaps by trading a few licks with the man, in those circumstances of accelerated intimacy which only we musicians know, I could test the accuracy of those fantasies up close. Besides, I had nothing else on. 

"Oh, all right then," I said. 

Sting lives in a beautiful 450-year-old Jacobean pile in Wiltshire. That's when he's not in Hampstead or New York or Los Angeles or Miami which, generally these days, he is not. He bought Lake House a few years ago after seeing an advert in Country Life. The previous owner, a sea captain, was living in one room only, probably unaware of the building's potential as the recording studio, practice room, band lodging house and fresh-flowered family home which it now is. Beyond the terraces and lawns, past the tropical conservatory, stocked with reptiles, the River Avon wanders casually through the grounds, passing the small, neat boathouse in which Sting does some of his lyric-writing. 

It's often said about the times in which we live, that you just cannot get the staff. But Sting clearly can. The front door is opened by an elegantly waistcoated butler called Louis, who also brings the tea. Later a plethora of cooks will serve lunch for the personal assistant and the nanny round a large cheerful table which also includes Sting, his wife Trudie Styler and the members of Sting's band. Dogs of various hues and sizes mill about, including a chest-height wolfhound. 

"I'm sorry?" 

I had met Sting before. This was in 1991, at the time of his album The Soul Cages. That was a sombre and introspective record, squeezed out after a sustained bout of writer's block and much preoccupied with the death of Sting's father. Sting himself seemed self-absorbed and remote and it was fairly clear that being interviewed was a pleasure he ranked right up there with root canal work. A jam was pretty much out of the question. 

These days, though, he meets your eye and he laughs a lot and he seems to have relaxed and warmed up. This would be a presumptuous thing to say on such scant evidence, except be a presumptuous thing to say on such scant evidence, except that you also detect it in his records. His last album, Ten Summoner's Tales, was written in a two-week blitz and, unlike knottier, more furrow browed albums in Sting's past emanated a simple, unfreighted pleasure in making short pieces of music fizz. The new one, Mercury Falling, though it cost him more effort (a year assembling the music a fortnight of eight-hour days writing the lyrics) does the same trick but, possibly, with still more delight. There are several songs here (notably Brought To My Senses and All Four Seasons which hook you immediately and indefinitely. 

What those records have in common is the small collection of supple musicians Sting has assembled around him since the termination of the Police, and Lake House. "We record in the old dining hall," he says. (We meanwhile, are in the front parlour, off the wood-panelled atrium.) "It' very cosy, very cramped. The fire's on, you can smell the food from the kitchen, the kids come in from school... I just find that better than the prison which is the average recording studio." 

The album mixes up pop and jazz. Sting says he was listening to nothing very much in the way of new music when he was making it. For one thing, he was too busy playing through Bach's lute suites on the guitar: "One or two hours a day: I'm not a very good guitarist but I can get through it." For another, at Sting's age (44), staying rigorously in touch with the cutting edge is not something you much care to bother with. 

"One record I really loved was Bruce's (Springsteen, that is). I wrote him a note saying, 'You bastard'. I hope he has the same feeling when he hears my record. But otherwise, I hear my children's music, I guess. I have to steel myself against going in there and saying, 'Turn that fucking row down.' Then I realise it's Blur, or Oasis, or Coolio. I'm hearing what's current through them and not because I choose to." 

The problem Sting faces (equably) is a familiar one for musicians of his generation: how you sustain life as a pop star into your forties and beyond. "There are songs on this record about accepting things you can't change. And there are songs about romantic situations that don't have a happy ending. It's not the standard fare of pop music at all. But if pop music is just about being in a gang or dancing or frivolous youth stuff, then I'm in the wrong business. If it's fuddy duddy music so be it. But this is what I am and I'm proud of it. I'm not afraid of being attacked or ridiculed. I've been there before. Views on me are very disparate: I'm either a decent man or a complete shit. The truth is I'm somewhere in the middle." 

Before last year's court case with Keith Moore, his accountant, money was not, Sting says, something he thought deeply about. "I like the freedom it gives you, but there are responsibilities attached to it too. But I can't sit at home every night and count the money. I couldn't do my work. How could you lose £6 million? Easy! Because I never look. I don't read my bank statements and I don't suppose you do either. What you have to remember is that I had 160 bank accounts at the time. "The whole business was very sad. Someone who worked for me for 15 years is now in Wandsworth Prison on a six-year sentence. It made me redefine what my wealth is. My wealth is my family and my close friends and my ability to play music. You can't steal those things. That's where my self-worth lies. I had an opportunity before I became famous to develop a life. I was a schoolteacher until I was 24. It's very important to me that I did that - that I had a mortgage, that I had a pension plan. I could still be that person. I could lead a perfectly normal life in my flat in Newcastle, playing my songs to my cat if that was it." 

After lunch, we went through to the old dining hall, where Sting and his band were rehearsing for their upcoming world tour. An engineer gestured to where a keyboard was already set up for me and pointed out the headphones I would need to wear and the miniature personal mixer with which I could adjust the sound balance to my own taste. I nodded knowledgeably, trying to affect the manner of someone entirely used to having his equipment silently and efficiently made ready for him, rather than having to hump it through the door and bolt it together himself. 

Apparently Sting had the idea early on that we would learn and perform something by the Cleaners from Venus. I was quietly relieved when this notion died out. Sting possesses no Cleaners from Venus records and thus has never heard "Mercury Girl" (on the Going to England album, Side 1, track 4). It was the Cleaners from Venus's "Every Breath You Take". It was also, quite substantially, Sting's "Every Breath You Take". Achingly beautiful, we thought, though Sting's lawyers might have been less enchanted. 

Instead we played Hounds of Winter, the opening track from Sting's new album. Just prior to lunch, Dominic Miller, the guitarist, had patiently written out the chords for me along with those for Seven Days. Many of them contained flattened fifths and sharpened elevenths and looked more like chemical formulae than chords. "Is this F sharp a major or a minor?" I had asked him, bravely. "It's neither," he said. 

Sting, of course, already has a perfectly good keyboard player - the jazz musician Kenny Kirkland. Actually, make that perfectly excellent. Kirkland sat opposite me, offering warm smiles of encouragement. He did not, it occurred to me early on, look like a man afraid for his job. Next to him was Dominic the guitarist and, behind some screens Vinnie Colaiuta on drums. Sting was on bass on a stool to my right, doing that pursed lip thing he does when he plays, managing to concentrate on the job, even with random keyboards going off in the background. 

Seven Days is in the devilishly tough 5/4 time signature - although, in the two run throughs we gave it, I like to think my contribution brought something of the more dependable 4/4 to the song. With Colaiuta flicking randomly at cymbals, there was little to do but cling on tight and hope not to get bucked.

Following this, my slightly high-voiced request for a slow blues in E went unanswered. Instead, we played the old Police song When the World Is Running Down (4/4, three chords, laughably easy actually) and She's Too Good For Me off the last Sting album (complicatedly stop/start; I was starting where I should have stopped and stopping where I should have started). Still I felt easier now. I had ceased trying to hide by gradually diminishing the volume of my own instrument. I was even beginning to feel free to rock slightly on my stool. But then something terrible happened: Kenny Kirkland took a solo.

It was during Nothing 'bout Me. For the most part, Kirkland had stuck with an organ sound, which meant we weren't competing for the same space. But now he hit the piano button and took off fast and fluid and tuneful. I looked down to check it wasn't my hands making that noise. But my hands were at that point lifting themselves away from the keyboard in shame and dropping slowly into my lap, where they remained for the next three minutes.

And then, completely without warning, we were into Every Breath You Take. "Don't be shy," Sting shouted above the noise and, galvanised, I went back to work, smoothly rotating those familiar chords albeit in the wrong key. A quick burst of the Match of the Day theme to close with, and it was all over.

"Obviously," I said to Sting in the hall on my way out, "you didn't want to say anything in front of Kenny, but if you need me, you know where to find me."