John Martyn is a folk singer and experimental guitarist, best known for his influential 1973 album Solid Air. He has worked with Lee 'Scratch' Perry, Eric Clapton and David Gilmour. His body has suffered years of alcohol abuse and he recently had a leg amputated after a cyst burst. He is touring the country from Sunday, finishing at London's Roundhouse on February 3, performing the Solid Air album each night.

Why do you think Solid Air remains so popular?
I’ve no idea. I approached it like any other album but it did very well. It was ahead of its time, I think, because it went plink plonk plink, when everyone else was going bang bang bang.

Is it true you weren’t happy with the album?
Yes, I didn’t like the singing. I thought I could do better. Since then, I’ve taught myself to sing. I suppose it does have a strange sort of charm for some people but it wasn’t what I was looking for. I was trying to be more grown-up. I wasn’t, though – I was still a nipper.

A lot of your music is otherworldly and druggy. Were you often in an altered state while making it?
I was in an altered state, period. I’m often in an altered state, to be honest. I like it. I’ve been like that all my life.

How did your guitar sound develop?
I think I’ve worn that out now. The backslap guitar thing was good. I hear it copied everywhere now and it makes me feel very good, man. I think: ‘Oh, they must have listened to me. Bless them. Oh, I hope they do well.’

Your voice sounds a bit like a saxophone. Is that deliberate?
No. I’ve always just tried to be a better singer than I was the day before. Now I’m getting old, the top two octaves in my range have gone, so I’m going low all the time.

How low can you go?
[Sings like a foghorn] Pretty f**king low. But I like it low. I think it puts a more masculine flavour on things.

Do modern folk singers treat you as a Godfather figure?
I don’t really know why the folk label has stuck. But new songwriters tend to like me, I think. I don’t really meet them, to be honest. I’m getting cranky and old, so I tend to arrive at a gig five minutes before I go on and leave two minutes after I come off. That’s the way I like it.

Some people associate folk music with beards and cardigans. How do you feel about that?
Oh, dear boy! Well, the beard I do have but not the cardigan. There are folky types with very long handknitted sweaters in various colours, so you could vomit a Spanish omelette down the front and no one would notice. And the sweaters are always five sizes too big, the wearers have a goatee beard and a beret and a complete inability to play guitar, and a friend playing bongos who’s even worse. There’s a certain genre like that and I don’t like it.

Are you more suited to a rock’n’roll lifestyle than folk?
I was never really a party animal, I was never that way inclined. I like a bit of company but I prefer it to be diverse rather than intra-social. It becomes almost incestuous after a while if you meet the same people every weekend, blah blah blah – it’s no good. It’s important to stretch the mind. Travel’s good for that.

You’ve moved around Britain a lot. Do you see yourself as a Northerner or a Southerner?
Oh, I’m definitely a Scotsman. Or a nut Londoner. I’m either a hardcore Scotsman or a very hardcore Londoner. I spent a lot of time hanging out with bad boys in London.

You worked with Lee ‘Scratch’ Perry. What’s he like?
He’s a lovely man. I can’t say a word against him. He’s a nice, sweet geezer. I mean, mad as a snake, but I love him, man.

You were also friends with the late musician Nick Drake.
Ah, my Nicky. He was beautiful. All the good thoughts people have about Nick are true.

How much has your drinking affected your life and career?
It’s been a problem for other people, I think, but not really for me. I’ve known people who’ve had problems with drugs. I hate heroin and crack cocaine. I just watch what it’s done to society and it’s horrid. It’s something I’ve always aimed to avoid. I tried it and it was a gas, but no thank you.

How has your life and touring been affected by your operation?
Travelling now is a real bitch. Anything more than a few hours and I hurt. I have to curtail the distances.

Is this tour a farewell tour?
No man, no, no, no. I’ll keep bugging you for a few years yet.