For nearly 40 years, music lovers have gazed at Joan Armatrading's guitar-playing, and marvelled at her assurance and control, the intense and feeling relationship she displays with her instrument: the complex and delicate chording on "Love and Affection"; the muscular dynamics of "Down to Zero"; the sweet and searching electric solos that punctuated her triumphant Albert Hall concert in 2003. But which guitarists does she admire? If such a virtuoso has a guitar hero, who can it be?
Joan fans will find out this week, as Radio 4 presents Joan Armatrading's Favourite Guitarists over five daily teatime slots. The sainted quintet are an eclectic throng. Mark Knopfler, originally of Dire Straits, is an obvious rocker. But John Williams, the classical axeman best known for the tremulous "Cavatina" on the soundtrack to The Deer Hunter? Bonnie Raitt, the flame-haired country singer of "Love Has no Pride"? Bert Jansch, the rumpled veteran folkie of Pentangle, the late-1960s band? And what the hell is Russell Lissack doing in the list? The twentysomething, floppy-fringed Essex vegetarian from Bloc Party? Why them and not E Clapton, J Beck, D Gilmour, BB King, J Marr or any of a score of others?
"Well of course I could have chosen five others, or 50," says Armatrading. "My list of favourite guitarists goes on for miles. But if you ask, 'Why those?' it's like the joke about the woman standing in the street, and a policeman walks up and stands beside her. She says, 'What have I done wrong?' and the policeman says, 'Lady, I got to stand somewhere.'"
The quintet (I suggest) comprise a guitarist of rock (Knopfler), folk (Jansch), blues (Raitt), classical music (Williams), and, in Lissack, a virtuoso of reverb, tremolo and other tricksy hi-tech stuff. Did they represent different music genres? "These are all wonderful guitarists no matter what style they play in. This isn't about pigeon-holing. I wanted to explore some varieties of guitar-playing. But the series is about people who play the instrument well and do something different with it."
Did she ask them, "How do you do that, on that song?" "No. I wanted to find out about their relationship with the instrument. Though I did ask Mark Knopfler how he felt about divulging his technique to audiences." How did he reply? "He just played the guitar on air. He demonstrates things by playing."
She established a warm rapport with Bonnie Raitt whose bottleneck slide guitar technique she much admires. She admits ruefully there there's a dearth of talented axewomen around today. "After Bonnie and me, I'm not sure where the list goes. She and I would both love to see more female guitarists coming forward."
John Williams earned a place in her list by being a man not lashed to the classical stave. "Classical musicians generally stick to a score, and many of them would panic if you told them, 'I want you to put a straight eight-bar blues in the middle of this piece', but John's different. He's one of the few who can improvise." Was she as versatile? Could she play a classical guitar piece, by Rodrigo or Villa-Lobos? "I probably could, but it'd sound more like "Joan Armatrading Plays Classical" than the real thing. And a classicist could look at one of my solos and reproduce it note-for-note, but it wouldn't sound the same. Because, you see, music is about feel."
Bert Jansch, the Glaswegian master of folk-baroque complication – his chord "voicings" and agile "string bends" suggest a musician with at least 10 fingers on his left hand – was an early influence. "What stays fresh about him down the years are his inventive tunings and the complexity of his playing. I was influenced by his open tunings, and used some of them on my first album."
That was Whatever's For Us. It came out in 1972, when the world first clapped eyes on the 22-year-old, St Kitts-born, Birmingham-reared Armatrading. From the outset she was wary of the media's attention, seldom gave interviews, refused to give details of her private life, and wrote love songs to a non-gender-specific "You". In the 21st century, her Wikipedia entry has nothing to offer under the "Private Life" slot beyond the information that she lives in Surrey. But now she's come out of her shell enough to front four documentaries, the first two for Radio 2, the third for Radio 4 – last autumn's Joan Armatrading's Favourite Choirs. Has she conquered her shyness? "If I hadn't grown at all as a person in the 37 years since my first album," says Armatrading tersely, "that would be a bit tragic."
And today she's sufficiently down with the kids to include Russell Lissack in her line-up. "I'd seen Bloc Party on television, but then I went on Later ... with Jools Holland and saw him play live. He was terrific. Yes he uses lots of pedals and wah-wahs, but so do I. A good guitarist uses that technology with taste and restraint, to extend what a guitar can do. It's more than just showing off."
Who is her favourite guitarist in terms of playing live in front of an audience? She makes a despairing noise. "People ask me that all the time, and I never have a straight answer. There's always a great long list in my head. But I think all my Top Tens would include Mark Knopfler and Muddy Waters."
Last question: did she ever play air guitar? "Oh yeah," laughs Armatrading, "I think everybody does, don't they?"
'Joan Armatrading's Favourite Guitarists' is on BBC Radio 4 every day this week at 3.45pm