At the bottom of the escalator in a North London tube station a long-haired Spanish boy is belting out The Long and Winding Road on an electric guitar. Ivor Cutler, who is taking me to lunch, sticks his fingers in his ears, screws up his face and howls: "Too loud, too loud."
As a member of the noise abatement society Cutler dislikes amplified music in public places. I wonder how the Beatles-loving busker would feel if he knew this old man with a screwed-up face was a friend of John Lennon’s who rode the Magical Mystery Tour bus.
Cutler is 81 now, and has become the curmudgeonly old man he has pretended to be for at least 40 years. In the week that Edwin Morgan, another octogenarian, was declared Scotland’s first National Poet I decide to pay a visit to Cutler - who has long been referred to as Scotland’s alternative poet laureate. Beloved by John Peel, befriended by the Beatles, Cutler has had a cult following since the 1960s. His fans have a tendency to recite his poems by heart, mimicking the refined west coast whisper familiar from his recordings and radio broadcasts.
Culter’s Scotland can be a land of parsimonious killjoys where small children are subjected to outrageous acts of violence - but he is still regarded as one of us. Although he has lived for decades in London he says he has "a foot in both countries". His publishers at a small press in Lancashire have warned me Cutler sometimes struggles with his memory - and organising an interview by phone proves laborious. But Cutler’s wit has not deserted him. I tell him I am excited to be meeting him. "Don’t get too excited. You might soil yourself," he says, with an old-man chuckle.
Cutler resides in a quiet street in Tufnell Park, North London, in a row of stucco-fronted terraced houses which hover indecisively between toughness and affluence. He is touched The Scotsman is coming and has made preparations. He answers the door in Gaelic and has decorated his tweed cap with five homemade badges and a large nylon sunflower. He has laid a whoopee cushion in an armchair waiting for me to sit on it. Five minutes into the interview he proposes marriage.
"Of course," I say brightly, eager to enter the spirit of things and not quite sure if he is serious.
One of the first things I notice in his overcrowded attic flat is a map of the Glasgow Underground. "You have a map of the Glasgow Underground," I say.
"Well, it’s a start," he answers.
His flat is a creative clutter of cartoons, scraps of poetry, masks, feathers and artists’ figurines.
"I cleaned the carpet for you," he says. "You should have seen it yesterday."
We begin to discuss his work and try to piece together the story of how he became a humorist.
He says: "I am one of those very lucky men who has lived the way I wanted. I had a rotten beginning in life. But all the people who become really good humorists will be people who have had a rotten time - not necessarily for ever, but they will have had a patch of time which leads them to start to find out what they are."
Born into a family of Eastern European Jews who settled in Greenock then moved to the Glasgow slums, he no longer considers himself a Jew. "A Jew is something to do with God. When you stop believing in God then you stop being one. I gave up religion."
Fear of anti-semitism stopped him from being a conscientious objector in the war, but he had to leave his wartime post as a navigator because of a compulsion to stare out of the windows sketching the clouds. When he was asked to operate a machine gun he was horrified and said: "I can’t do that." He finished his wartime service in a munitions factory in Pollokshaws where, he says, "I was beginning to relax and become a human being." After the war he drifted into teaching, but rebelled against the rigidity and violence of the 1950s schooling system.
"On the day I left I cut my belt into 50 pieces. There were 50 kids in the class and as a leaving present I gave each of them a fiftieth of my belt. Then I had the pleasure of their pleasure of seeing the mighty fallen."
Instead Cutler went to work at Summerhill, the radical Suffolk school founded by AS Neill where lessons are optional and pupils and teachers are equal. Cutler describes Neill as "the only man I have every thought to call a saint. When I came across Neill’s book I thought it was like fairyland. I decided to go and find a job there. I got bored after two years because there were no women there and I enjoy women. I was a pretty shy man."
He moved to London, married and had two children. In his late thirties he recorded his first single.
Cutler is finding it hard to concentrate on his life story and be serious, and his mischievous interjections have me and the Scotsman photographer in gales of laughter. "I hope I’m not spitting on you," he says at one point. "No, not at all," I reply. "Well, in that case I’ll try harder," he says.
He admits he finds questions difficult these days: "This thing about answering questions does something to my mind," he says. "If I wait for four or seven minutes the word usually comes back. I have begun to think of it in terms of a river."
He offers to sing to me and to play on the beautiful wooden harmonium in the centre of the room.
"Is it the one you use for concerts?" I ask. "No," he replies sternly. "It’s far too expensive."
How would he describe his voice? "Very good," he booms and begins to sing in a resonant baritone.
Where the river bends
The blind men fall in...
Where the river bends
The blind men fall in.
I am concerned Cutler is finding the interview exhausting so I propose a trip out for lunch. Before we leave he insists on showing me the bathroom, which also overflows with books, papers, pinned-up cartoons and miscellaneous clutter. "I haven’t had a bath for 30 years," he tells me.
On the toilet there’s a cartoon he wrote for Private Eye. It says: "Human beings have a tube in the middle. When they put food in they like to be with other people, but when it comes out they sit alone."
In the bathtub is a large blow-up photograph of a group of 1960s debutantes with backcombed haystack hair. "I like to look at them," he says. "Forced to go to parties and marry rich men when they could be doing something more interesting. It’s so sad."
Still resisting the charm of the bourgeosie, Cutler is appalled when I suggest we catch a taxi to the centre of town. He sets off through the streets at a brisk trot and I find myself scuttling to keep up. He tells me he likes public transport.
"I like to go up to people on the tube and ask them if they write poetry. You’d be surprised. It’s about 50 per cent."
On the Northern Line he goes up to one middle-aged woman and whispers in her ear, telling her she looks like a princess in her sparkly velvet dress. As we step off the train he glances back and sees that she is smiling. "Well, that worked well," he says.
Over lunch in the Photographers Gallery in Soho we discuss his status as a counter-cultural icon. I ask him how he fitted in with the drug-taking 1960s.
"I seemed to do very well without having to do anything like that," he says. "Creativity for me must be clarity and not be jazzed up." I ask what sort of people he thinks like his work. "I would say a person who had the capacity of a child ...I am a child," he says firmly, fixing me with his pebble-glass stare.
In the afternoon we spend a riotous hour at the National Gallery, looking at the pictures. Cutler’s mind seems to work best when he has a visual stimulus in front of him and he shambles along, holding my arm and mumbling imaginary captions to the nation’s art treasures.
"Look, that man is peeing, see his face," he says. "And that little boy is saying to the woman: ‘Mammy, mammy. Daddy has just farted.’"
But it isn’t just pictures that excite him. Cutler loves watching people and the sight of a pair of contented little girls sketching almost moves him to tears.
After I leave Ivor Cutler I worry about the marriage proposal and wonder if my acceptance has created unnecessary confusion in his mind. I telephone before leaving London and thank him for a wonderful day.
"I think I got rather excited," he says. "It’s nice to laugh with people. It is people that give me such pleasure. But I don’t think we should get married straight away."
• A Nice Wee Present from Scotland and Under the Spigot, Arc Publications, 4