There are plenty of teachers around with unusual hob-bies, but it’s hard to beat Paul McCarthy’s. Look at the photo on the right and you might get a clue but prob-ably only a clue.

You might guess that the technology teacher is keen on those fantastically ornate fairground organs that fascinate kids and provide a cheery musical backdrop at summer steam rallies up and down the land. But what you probably would not guess is that he has built no fewer than 130, which are now in collections all over the world.

And in the esoteric world of fairground organs, Paul is a big name. “After a while, you suddenly realise this,” he says. “You talk about making cars, and you talk about Triumphs or Minis or Fords. I was standing in the middle of a group of organ enthusiasts and one of them said: ‘well, a McCarthy’s got a so and-so’ and I thought ‘crikey!’

“In organ enthusiasts’ terms I’m a well-known name. That’s surprising the first time you hear it, and it takes you back.”

The trouble with organ building, as Paul discovered, is that the instruments command high prices, but they are expensive to make because of the workmanship involved.

The process he uses to make the pipes, for instance, was developed in 1896. Each organ, and each pipe, has to have the same quality of sound and tone and don’t even ask about the possible complications of getting the cardboard music to run through correctly. “It’s a labour of love,” says Paul. And that is why he has now gradually returned to full-time teaching, from being a full-time organ maker.

He makes everything from scratch, including the all-important pipes, and has a catalogue for would-be buyers.

The smallest organ he builds costs pound;950, while the largest he made would now sell for about pound;25,000. “I did that one 10 years ago. It was about 12ft long with 320 pipes, drums and cymbals. It had an elaborate front with two bellringers. It sounds like a lot of money but it would take nine to 12 months to build one of those.”

He adds: “You have to work some long hours to survive doing it it’s a cottage industry. People forget how long they take to build. From an economic point of view it’s a disaster but very satisfying.”

Paul qualified as a teacher in 1980, after working as a lab technician, and started making his first organ at the same time. What set him on such an unusual path?

“I started out being interested in steam trains, and then traction engine rallies. I got more interested in that and the fairground organs, and thought I wouldn’t mind one.

“But at the time there wasn’t much money about, and not much information on how to build one, either. So I experimented with church organ building there are a lot of similarities and it evolved. It’s easier now with the internet.”

Six years after starting work as a teacher, he says: “I decided to take the bull by the horns and gave up teaching to build them full-time, but I did a bit of supply as well.

“About four years ago I went to do a couple of days’ supply at Kings’ School in Winchester and I’ve been there ever since, full-time since last year. Organ building is much more of a hobby now.”

Where Paul once had a workshop on a farm, these days the two organs he is still working on are being built at home in Hampshire. Dorothy, his wife, and Enfys, his mother, also work there, hand cutting the thick rolls of card sheet music that the organs “read” to play the tunes.

Even in its new status as a hobby, the fairground organ accounts for much of the McCarthys’ home life. Paul’s own organ (22 notes and four feet long) is on loan to a friend and he is harbouring plans to construct another. He has found himself volunteering at Hollycombe, an open-air steam museum in Hampshire, where the organs have been little maintained in the five years since its founder died.

And the couple enjoy days out with a fairground organ, perhaps a small hand turned one. “We go out to fetes and things like that, occasional traction engine rallies, Victorian fairs and so on. We do get out and about and enjoy doing it. We used to do it for business, but now it’s for fun.”

Teaching, you sense, is fun for him as well, especially after solitary years turning pipes in a workshop. “I enjoy the teaching I do at Kings’, and the staff are really friendly,” says Paul.

“I think some of the pupils know what I do we did a leavers’ ball last year with a fairground theme, and someone said: ‘I hear you have a fairground organ.’ I took it up and I think they were a bit gobsmacked. Some of the kids were fascinated, some thought I was a bit crazy.”

Though Paul is putting teaching first at present “that’s crucial” the organs will continue to play a major role in his life. “I’ll probably do it more again when I retire,” he says, adding: “Hopefully the organs will last a lot longer than I do. They’re likely to belong to enthusiasts so they’ll be well preserved.”