JAZZ. Cool. It's hard to say one without the other. Try it.

Jazz ... cool ... Nod your head at the same time, slowly though, don't let's do anything too quickly. Hmm ... Nice ...

I am wondering quite how on earth jazz continually pulls this association off, as I nod my head and tap my feet inside St John's Church, in Totnes.

Jazz cats are cool cats, laid back, sunglasses on indoors, finger-snapping, toe-tapping dudes. Still. After all these years, and long after the last zoot suit was retired from active service.

These days most people are only exposed to jazz at summer festivals, invariably outdoors, often overrun by rotund men drinking real ale, or on the wireless, where Jazz FM struggles constantly not to become a parody of that Fast Show sketch which beat its presenters to it.

It remains impenetrable to many, a muddled cacophony from a bygone age. My wife, to pick a member of the Human Race entirely at random, actually claims to find listening to jazz 'stressful'.

So how does something so far out of the mainstream now, so far removed from anything the kids might be up to, manage to remain, well, cool?

Part of the answer lies in the fact that jazz, and the coterie of now infamous musicians who started breaking new ground in the 1940s and 50s, sort of invented its modern definition when Charlie Parker's 1947 platter Cool Blues first made the distinction between it and hot jazz, which has not weathered so well.

When Miles Davis released The Birth of Cool in 1950 that word was becoming more commonly and intrinsically linked to the music — and its creators. To a great extent that is the association which remains.

As an etymological aside, the derivation of the word 'cool' dates back to a standard English form at the time of Beowulf, as a metaphor for being unexcited, calm or dispassionate. It could also be argued that, a certain wife excepted, these are the sorts of feelings which jazz evokes in the listener.

From a personal point of view, I feel emotionally equipped to find jazz cool because I was exposed to it at an early age and, like the son of a lion tamer, learned not to fear the beast. My dad kept a couple of saxes in the loft to remind him of what happens to such things when you get married, and filled the time until he could retire and play them again in peace by listening to jazz records.

Thus I was weaned on the greats: Parker, Davis, Coltrane, Monk. As it turned out, this was not normal, but it has come in handy at various points in my adult life.

Not least of which is inside this church, where I am sitting nodding my head and tapping my feet. If I had been the sort of person who was apparently raised exclusively on, oh I don't know, Max Bygraves, I might be feeling stressed.

But I'm not. I am unexcited and calm. Cool even.

The members of Totnes Jazz Workshop are a playing a part in that, with a faithful rendition of a familiar classic, Watermelon Man, originally by Herbie Hancock.

Tonight they comprise a double bass, keyboard, guitar, two flutes, a drummer, four saxophones, two trumpets, one trombone, a clarinet and another sax, possibly a soprano.

That adds up to quite a sound bouncing off the low roof inside the main church room, which makes it a good job it is a pleasant one.

At various points during the course of the tune, Fred, who is standing in front of the musicians with his back to me and the rest of the congregation of two, points to one of them and invites them to improvise.

Now improvisation is one of those things which divides opinion on jazz. Some people love the fact that the musicians take off on flights of fancy, experimenting and composing as they go along until it's someone else's turn. Some do not.

And, sometimes, that goes for the musicians themselves.

"Every now and then we'll point to someone to improvise. Some of the experienced ones are all right, but some of our musicians are really only starting to get to know their instruments," Fred tells me during a break when long-time member Nick takes over at the front.

"You point at some and they freeze, or others get a couple of bars in and then they forget what they were doing.

"It's about getting people out of their shell really. Classically trained musicians don't always like it. We play all the wrong notes for them.

"It's about improvising, but really it's about enjoyment, playing together and enjoying the music."

They have been doing that since the early 1970s, in various settings and guises until they settled here, in a church, a few years ago.

"The acoustics in here are awful," says Fred, leaning over and shouting in my ear, "although I think perhaps you get used to it after a while. When we go and play outside, you're like, ah that's what it sounds like."

Nick is struggling to get across what Blue Panther should sound like on a more fundamental level.

"It's dee-dah, dee-dah, dee-dah-dum," he says, placing emphasis where it should properly be.

"You're playing de-dah, de-dah, where it's actually dee-dah ... dee-dah..."

"It's based on the exams for people learning improvisation," he adds by way of explanation in my direction, holding up a big paperback book called Jazz Works. "There are plenty of strategic gaps for people to fill."

And then he turns. "Ready? One, two, a one, two, three, four..."

They nail the dee-dah, dee-dah, dee-dah-dum bit this time, and even fit in a few improvs along the line. One of them comes from Jim, who does a bit with his trombone before placing it in the metal stand in front of him. He pulls a strained face at me and, jokingly, puts his fingers in his ears. It's really not that bad.

Just at the point at which the actual playing of music has given way to just a discussion about it, Nick promises more practice before Fred resumes pointing duties.

"It's a great room for preaching," Nick says with a wry smile as we observe goings on from behind the glass doors leading into the church, from where the acoustics are less obviously awful.

"I've probably been coming here the longest. It was started by a group of enthusiastic amateurs who wanted to get into improvisation.

"We all just stuck together when the college stopped doing it as a night school class. We used to be just a group of men for a long time. For some reason, the more women who join, the better the atmosphere in the group."

For a group of artistic types they are indeed a noticeably amiable bunch. I ascribe some of that to the music they are playing, and also to the fact that they are still learning how to 'do' improvisation. It's not something that comes naturally, even if you are a really good musician.

Jojo is a really good musician, and more than once tonight I have noticed her spurn Fred's invitations like a teenage wallflower at a school disco. And this from someone who has reached her Grade 8 certificate in piano.

"I just get scared when they ask," she tells me. "I might have gone a long way with the piano but I'm new to improvisation. It's all about learning the basics again."

Jojo has been not improvising tonight on her flute, though, standing next to Joy at the far left of the ensemble. Joy has no instrument to hand at all, but has been joining in nonetheless.

Scat singing, another of those things which scares some people off jazz. In here, though, beneath the board displaying one of the hymn numbers left over from Sunday, singing along seems perfectly natural.

"It's really been a wonderful experience," Joy tells me after Fred has pointed his final point and instruments are placed back into velvet covered slots in cases of various shapes and sizes.

"Nobody laughs if you get it wrong, we're all in it together. I do sing, always have, all different kinds of styles, but this is new to me.

"In scat singing you just have to experiment. It can be hard, sometimes, especially if you drift off for a bit and don't pay attention.

"But that's what I like about the workshop. It's a workshop. Nobody judges you."

Not like folk are inclined to do in the outside world, anyway.

I wonder if people ever make assumptions about Jim when they notice he walks slowly and deliberately with a pronounced limp. As he returns his trombone and trumpet to the open cases arranged on the front row of chairs he tells me why.

"I messed up my spine in an accident at work. I don't have any feeling in my left hand, which is what makes playing the sax so difficult. It's a shame because improvisation is much easier on the sax. You just play any old thing and people clap."

There is nothing obviously wrong with Jim's funny bone, nor his sense of determination. In spite of the obvious impediment, he decided to play the saxophone by sight and sound, if not touch.

"I learned to play in a mirror," he says, as though that was the obvious thing to do. "Which is okay as long as you're looking in a mirror. When I went outside it became more difficult.

"The trombone and trumpet are much easier to play as there is less emphasis on the left hand."

A native of London, Jim moved to South Devon 13 years ago, after the accident, and has also since taught himself to play the flugelhorn and flute. "We used to go down to the band room when I was in the army and just mess about on the instruments. But I taught myself, never had a lesson."

Well, lessons can only take you so far where jazz improvisation is concerned anyway, if Jojo is anything to go by.

She has let another week go without responding to Fred's gestures, which he is still only pretending to take to heart.

"I just don't feel that confident yet," she tells him as Fred shuts the heavy church doors behind us, "but I might have a go next week."

"Cool," I say without thinking, and nod my head. "Cool."