The morning after, he turned 40, a birthday by which most singers who are going to make it have already done so. On a heavier night for traffic, Nelson would have joined the already lengthy list of musicians gathered up somewhere near their prime. You'd have found his name near the bottom, in small print, way below his fellow Texan Buddy Holly, or Patsy Cline, who made his song "Crazy" famous. It's convenient, if not quite accurate, to date the birth of the Willie Nelson of legend to that night on the snowy, deserted asphalt. Actually, the troubadour had already begun roping a bandana round his brow and wearing his auburn hair down between his shoulder blades. But it's true that most of the income on which the Internal Revenue Service famously computed a tax shortfall of $32m was earned after that half-hearted attempt to kill himself.
In the 1960s he made a tidy living from other crooners' polite recordings of his melancholy songs. In the 1970s he blithely reinvented country music, sang gospel, blues, Broadway tunes, and shifted more records than anyone in a hat had ever managed. He earnt the tag of outlaw and haemorrhaged the money.
A few years ago there were signs of creative wilt, but then he hired Don Was, jumpstart producer to vintage stars with engine trouble, and came up with Across the Borderline. It was a stunning way to kick off his seventh decade, which may be his finest yet as he scratches away at the upper limit of what we regard as an acceptable age for productive rebellion. (The new album, Spirit, is another beauty.) Willie Nelson has been 63 for a fortnight. He has snow-white eyebrows and a ragged matching beard. The odd Delta bluesman may have been ploughing on for even longer, but no one who started out at the same time as Elvis Presley still pounds the circuit with quite such an air of not knowing what the hell else they'd be doing.
"He's the paradigm of what a contemporary American artist should really be about," says Don Was down the line from LA. "He completely shunned the music centres and set up his own little station on the frontier. He will not play by the rules. That's really what they started America for." It makes sense that he's a national institution. Sinatra sang at his sixtieth. Last year some Seattle bands made a grungey tribute album. When recently arrested for marijuana possession (a charge he'd never deny: he once smoked a joint on the White House roof), the case was thrown out of court.
Last weekend brought Willie Nelson and Family's never-ending tour to these shores. On Saturday night the paterfamilias shambled on to the Albert Hall stage, shod in chunky grey trainers and baring sturdy, wrinkled old man's biceps. The show over, Nelson pumped paws and signed programmes for fans variously distinguished by nose rings, blue rinses, beerguts and scrubbed pre-pubertal complexions. No high priest of popular music presides over a broader church.
It's midnight by the time the glad-handing is done, but the promotional chores are not over. Out on the road Nelson sets aside the small hours for doing interviews.
We traipse through the old building's network of corridors to a door marked Conductor's Room. Imagine the talent that has used this cupboard down the years. Its current occupant perches on the sofa. His much younger wife Annie, a make-up artist he met on the set of a movie, takes the chair; and the pony-tailed henchman leans against the door jamb.
After the concert: Willie Nelson and Family, the interview.
The first time Nelson performed in London, "if I'm not mistaken, I came with Hank Snow and we played the Royal Albert Hall". Ringo Starr popped backstage: maybe he'd heard that Snow, a country legend born in 1914, hailed from Liverpool, Nova Scotia. The Beatle "came in the dressing room, and said 'hello', and that's about it. He didn't know me from Adam."
Nelson set about distinguishing himself from Adam at an early age. His parents were divorced, so he and his sister Bobbie were brought up by his father's parents. Grand- father was a blacksmith with a gas station out the front on the highway. Little Willie "would turn the bellows that fire the coals that heat the horse shoes to shape them, and I helped him sharpen a lot of ploughs". But both grand- parents also taught music: "They could read the 'do re mi fa so la' to the shape notes, and teach legitimate singers to sing." Their best ever pupil got a Stella guitar at five. "The strings were an inch off, so my fingers got toughened up early."
In fact, his first talent was in words rather than music. "That was the first thing that he was really so very good at," says Bobbie Nelson, his sister and pianist, who exudes the same air of slow serenity that's part of the Texan inheritance. (Another part, thanks to the state's ethnic diversity, is the catholic taste in music, which helps to explain the baffling news that Nelson's next release will be an album of reggae songs.) "Before I learnt to play an instrument I was writing poems," her brother confirms. "I was writing about things that I had no idea of." "Infidelity and betrayal," his autobiography says - straight into the wrist-slitting country groove. And the first song, does he remember it? "Sure." So how does it go? "Can't tell you. If it was that good I'd be doing it in the show."
His grandfather died when Willie was six. Perhaps out of proxy-paternal feeling, the town's other blacksmith invited him, aged eight, to join the local Bohemian polka outfit. "I've often wondered why John Raycjeck wanted me in that band, unless he just thought maybe I was going to be in some band somewhere and maybe wanted to give me a little experience of what it was all like. I played rhythm guitar in a band where you had a big drum, and a big oom-pa horn. There was no way that I could be heard. I didn't care. I was getting paid, and they couldn't hear my mistakes."
For his silent errors he took home $8 a night: not bad, pro rata, compared with the weekly wage of $50 he earnt as a desk-bound songwriter when he first went to Nashville in 1960. But that was years away. He formed his first family band, with Bobbie, her high-school husband, the football coach and their dad, and got the touring habit. It didn't take him far enough, though, and at 16 he joined the US Air Force: "It was a way out of town. I had to get my grandmother to sign for me to go I was so young." He did a tour of Korea and, as the Nashville suits would discover, responded poorly to authority: "Everything was disciplinary and you had a lot of orders to follow, and I was not used to doing that."
Back home he worked on a farm in Waco and sold encyclopaedias and vacuum cleaners door to door. But having DJ-ed in his teens, he took it up again and for several years he flitted from station to station and state to state. In 1956, 40 years ago, he pressed his own single and hawked it over the airwaves in Vancouver, Washington. "I think I sold four or five hundred at a dollar apiece, and I threw in an eight by ten glossy."
There was marriage, children, drinking, trailer parks and penury, but the songwriting gathered pace. Commuting from Pasadena to perform over in Houston, he composed in the car, and in one week he wrote "Crazy", "Night Life" and "Funny How Time Slips Away", the rights to which would keep someone less spendthrift in moderate comfort for life. "That was a nice week." Did he know "Crazy" was that good a song? "Once I found the chords to it: I heard some chords in my mind and so I went to the guitar and tried to find them and it took a little while. The words came actually quicker than the chord changes."
Pretty soon he was in Nashville, writing songs for a publisher that others would record. When Faron Young gave him his first hit, the songwriter, $20,000 richer, tracked the singer down to Tootsie's Orchid Lounge and kissed him on the lips. Nashville had its first taste of Nelson's unorthodoxy. Though financially secure, his own singing career stayed stubbornly in neutral: a contract with RCA tied him up for 18 underpromoted albums. His voice's nasal phrasing was too loose and interpretive for regimental Nashville, and when his house burnt down two days before Christmas in 1970, he needed no further encouragement to slip home to Austin and grow his hair.
"It was a way to blend. I felt like if I was going to be there and really relax and do what I wanted to do, it was a good time to do it because the audiences were definitely not dressing up. So I didn't see the need to do it, because I really wasn't trying to impress anybody." And yet this was when he started to do just that: he switched labels in 1973 and spent the rest of the decade cooking up albums done to his own specifications - not the overdone style of Nashville but rare, almost raw. Shotgun Willie was a shot across the bows, then Red Headed Stranger went gold. Wanted: The Outlaws, made with fellow troublemaker and most frequent collaborator Waylon Jennings, was the first country album to sell a million. Stardust, a collection of covers, defied all dire warnings of disaster.
The money now avalanched into his wallet, but never settled. "I didn't keep it. It sort of went through me. A lot of people had a good time, including me. I don't regret it. I still try to throw it away quicker than I make it, but so far I haven't been able to do that." At the end of the 1970s, the IRS decided that Nelson owed them. He's often been portrayed as a financial incompetent, but he blames, and indeed sued, the people he hired to be competent for him. "It was bad bookkeeping on their part. I had an accountant who didn't tell me the right thing to do. He had me in some tax shelters and things that were disallowed, and it was really not that good advice." To settle his debt, reduced to about $9m, he did not in the end, as has been widely misreported, have to auction off his studio, golf course, western town, house and fishing camp. But he did hurry out a compilation called The IRS Tapes: Who'll Buy My Memories. The 1980s found him diversifying into film (soundtracks and acting) and the annual Farm Aid benefit to help America's struggling rural communities like the one into which he was born.
The constant throughout has been his obedience to his twin mistresses, writing and the road. In 40 years he has written in the order of 2,000 songs, roughly one a week, though "actually I'd skip a few weeks and then maybe write six or seven in a day". There are far more than can ever be recorded. Spirit, the new album, starts with three songs remembered from 15 years ago. The nearly completed reggae album rescues forgotten tunes from the early Sixties. "He probably wrote 600 songs in that period," says the album's progenitor Don Was. "There are 300 sitting there that no one's ever heard and he simply didn't have time to record. But the quality doesn't diminish. There were three or four that he really didn't remember writing." They're still mostly sad meditations on lost love and broken dreams. Does it all go back to his parents' divorce? "I can't blame it on them. I don't know. I'm a country songwriter and we write cry-in-your-beer songs. That's what we do. Something that you can slow dance to."
Like Eric Clapton, a more frequent occupant of the Albert Hall, he lost a son a few years ago. Where Willie had failed to kill himself at 39, Billy succeeded at 33. But unlike Clapton, there have been no cathartic songs on the subject. Miraculously, Nelson has kept up an air of unsullied contentment. He now has two more young sons, is doing what he enjoys and doesn't see the point of retirement. "I can't see what I'd be retiring to or from." The words from "Crazy" (which Patsy Cline hated when she first heard his demo) have never rung more true. "Worry, why in the world should I worry?" And there have been no more nights spent supine on the tarmac. "If you get by one time there's no need pushing your luck. So I haven't laid in the street any more."
n 'Spirit' is released on Island Records, 3 June. Willie Nelson appears on 'Later With Jools Holland' tonight, 11.30pm BBC2Reuse content