That tells you everything’

others. Martyn once told me he was bequeathed a sense of decency from his father and a wandering morality from his mother, not to mention a weakness for alcohol. Billy Connolly befriended Martyn on the Glasgow folk scene. “He was still Iain McGeachy then,” says Connolly. “He was scared he’d become alcoholic, because his father was alcoholic.”

Martyn said: “It runs in the family, from my grandmother on down. My old man went at 84 and he was still drinking, big time. At first I drank because I was nervous performing, then the lifestyle got hold of me.”

This was all to come. At Shawlands Academy, McGeachy was an outgoing, exceptionally bright pupil. In 1963 he was one of three members of Class 3B1 chosen to represent the school in the TV quiz show Round Up. He was selected for a pilot project to study Latin and French, and in 1964 was the top English pupil. Although natural university material, he was already lost to music. “We hung out at a cafe in Calder Street, smoking and playing the jukebox,” says Thompson. “Later we’d go to folk clubs together and have fun. He was instantly quite impressive.”

He strolled around town in a sheepskin coat with a fur collar and stripey jeans, guitar in hand. By 1966 he was making forays to the Glasgow Folk Centre on Montrose Street, Clive’s Incredible Folk Club on Sauchiehall Street, the Scotia on Stockwell Street and the Crown in Edinburgh. His patron was the Falstaffian

folkie Hamish Imlach, who allowed Martyn to perform before his own sets and who grumbled good-naturedly about the curly-haired kid who left sweetie wrappers in his car.

From Imlach he learned stage presence, a robust finger-picking guitar style and how to live large. Good food, and plenty of it. Open house, with various intoxicants on tap.

Come all ye, and last man standing wins. Wit and staying power were precious metals, prized above all things.

“John had a wee bit of a swagger about him that was rare in one so young,” says his contemporary, the singer-songwriter Rab Noakes. “It wasn’t anything obnoxious, he was just quite cool and aware of his capabilities. From an early age he knew how to hold people’s attention.”

On stage he had good patter and a few flashy tricks. “He did an instrumental on the guitar using the capo, he’d slide it up and down, going up a half tone each time,” says Connolly. Inspired by Bob Dylan, he was already writing. Connolly recalls Golden Girl, which appeared on Martyn’s first album. “I wandered in the green stream that meanders round my mind,” he sings. “Ah, he was amazing.”

A young man in a hurry, by spring 1967 he had moved to London. Rechristened John Martyn at his manager’s suggestion, he became a boisterous fixture at folk hubs Les Cousins and the Troubadour, and was quickly signed to Island Records. His debut album, London Conversation, arrived in late 1967. Martyn would walk through Soho with the record tucked under his arm. “It all happened quite quickly,” says Fiona McGeachy. “We were awful proud of him. I would lie and listen to his music at night on my gramophone. I really worshipped him.”

London was about transformation. His rather refined Glasgow south side accent quickly came under assault. Depending on the context, he could sound like a Cockney barrow boy or a hard case from Barlinnie.

“He would revert, it was very schizophrenic,” says Thompson, who had also moved south. “It’s partly a musical thing, picking up on the tone, and partly a deep-rooted insecurity to be liked and accepted. Being John, he took it to staggering lengths. He had different personalities for different things.”

His music also evolved. In 1969, aged 20, he married fellow singer Beverley Kutner, becoming stepfather to her baby son Wesley. The couple made two modestly successful albums together but Martyn was uninterested in sharing the limelight. In 1971 he embarked on a streak of remarkable solo albums, often with his closest musically ally, former Pentangle double bassist Danny Thompson.

Moving out of the folk clubs to the university circuit, his music became an exploration in sound as much as song. His vocals stretched and coarsened, taking on the cadences of the saxophone. “He had a very pretty voice, which irked him a bit,” says Thompson. “He wanted to sound rougher.”

He experimented with Echoplex, a tape delay effect which enabled him to coat his acoustic guitar in layers of spiralling reverb, a technique since popularised by KT Tunstall and Ed Sheeran. Floating between folk, jazz, soul and blues, the music was bewitching, but he often appeared hellbent on subverting its beauty. “He’d sing

A more abrasive personality was beginning to appear. Split personality is too strong. John was maybe a series of inventions of characters

a beautiful song like Couldn’t Love You More, he’d be way into it, and after he finished he’d belch,” says Danny Thompson. “He didn’t want you to see his soft underbelly.”

BLESS the Weather, Solid Air and One World are masterpieces, but virtually everything Martyn released between 1969 and 1980 is essential. There was plenty of acclaim but no hits. He followed the music rather than the money.

During this period he often returned home, to work and play. When he and Danny Thompson visited Glasgow, they’d stay at Tantallon Road rather than a hotel. “We’d wake up early, breakfast was porridge, prepared by his wonderful, much loved gran,” the bassist recalls. “Then off in a black cab for a ride out to a country spot where we jumped over the dry stone wall, then across the fields to a shallow stream. He flicked his bamboo fishing stick until six brown trout lay on the bank. Back across the fields and into the nearest pub, two pints and a return cab to number 10. ‘Hello, Gran, trout for tea!’

“A bit of banter then off to the local bowling green. We’d play and gamble with serious competitiveness. It was the same with snooker. Then we’d ride into Glasgow and enjoy the Scotia Bar, or the Victoria. We’d have a play and get completely pissed and share the oxygen.” He laughs. “I don’t want to make out that it was very mumsy. We used to have serious fights as well. I’ve been nutted by him.”

During this time he and Beverley had two children, Mhairi and Spencer. The family moved from Hampstead, in north London, to Hastings, and finally to Heathfield, in east Sussex. As the music soared, so Martyn’s behaviour became more extreme and unpredictable, exacerbated by alcoholism and hard drugs.

“A personality was beginning to appear that was more abrasive,” says Noakes. “The accent changed, there was a bit of, who are you trying to be? Split personality is too strong. John was maybe a series of inventions of characters.”

There is a tendency to romanticise Martyn but some things should not be airbrushed. The loveable rogue persona played out on stage and in bars could curdle into something far nastier, especially behind closed doors. Not only was he an unfaithful and largely absent husband; he was also an abusive one.

When Beverley fled the marriage in 1979, she feared for her life. “I slipped my feet into my son’s boots and ran to the police station,” she told me. “I could never go back, but it left me relying on state benefits. It was hard. He mistrusted women and so treated them really badly, physically and mentally.”

Newly divorced, Martyn bunked with Phil Collins while they worked on the rawly emotional Grace and Danger. Afterwards he briefly moved back to Tantallon Road, where his father cut an increasingly eccentric figure. At one hometown show, Tommy exited halfway through, informing his son loudly that he was leaving. In 1982 Martyn settled in a cottage by the church in Roberton, a village in the Borders.

HE had gone bankrupt, lost his house, broken his neck and split his head open while swimming. The determination to experiment musically remained undimmed, but the muse had become a less attentive mistress. Most significantly, in 2003 his right leg was amputated below the knee, when septicaemia ravaged his system. By then, Martyn was living in Thomastown in Kilkenny with his partner Teresa. In the beer garden of his local, Carroll’s, as he outlined his affinity to Buddhism, he drained pints of cider into which he periodically dumped tumblers of vodka.

There was certainly wildness lurking there, but also courtliness, wit, erudition and refinement. Weighing more than 20 stones, scarred and battered, he walked with the aid of a prosthetic and a huge staff, but any hint of pity was swiftly stamped on. “I’ve had a wonderful time,” he said. “I can’t argue at all about what life’s dealt me.”

Martyn continued to tour in a wheelchair even as his health deteriorated. He died of pneumonia on January 29, 2009, aged 60, weeks after being awarded an OBE. It was a rare official accolade for the ultimate musician’s musician, lauded by Eric Clapton, The Cure’s Robert Smith and Dave Gilmour, but forever on the cult side of the mainstream. “He’s not recognised as much as you might expect for someone who has had moments of genius and created his own pathway,” says Donald Shaw, Celtic Connections’ artistic director. “He’s much loved, but in an underground way.”

Martyn always said he was happy being the connoisseur’s choice. Linda Thompson isn’t so sure. “He thought he was going to be famous. I think he aspired to that. Why wouldn’t he? He was very handsome, he was brilliant – but it didn’t take, and I think he was puzzled by that. He didn’t help himself, of course, with that slightly self-destructive Glaswegian thing. Billy Connolly had it, too, but he drew back from it. My friend Gerry Rafferty had it in spades. John shot himself in the foot constantly.”

Is Martyn’s career, so replete with youthful promise, ultimately a story of wasted opportunity? Danny Thompson, who will be anchoring the house band at Celtic Connections, shakes his head. “No. I understand other people feeling that, but you have to be true to yourself and live your own life. John never pretended to be anything that he wasn’t. People hear all these different stories and say, ‘What was John really like?’ If you really want to know what he was like, listen to the songs. That tells you everything about the man. It’s music of the heart.”

Grace and Danger: A Celebration of John Martyn, Glasgow Royal Concert Hall, tomorrow

Above: Billy Connolly, who befriended Martyn, left, who told him he was scared he would become alcoholic, because his father was alcoholic