How did you come to write the musical It's a Wonderful Life? Indeed, it was a tough job but somebody had to do it. My first staged musical, based on the novel Elmer Gantry was on at the Gate Theatre in 1986. Matthew Francis, who has co-written the book and lyrics on It's a Wonderful Life, had commissioned the piece for Chichester and the Gate picked up on it. We ran into a subsequent rights problem – as you do - when a producer tried to take it into the West End . He asked me what I would like to do as a musical instead and I suggested this one. 23 years on and here we are. Piece of cake.

Do you think a musical treatment adds to the audience’s pleasure? Does it place more emphasis on the characters or on the situations?
It only helps if the music is actually good. That is a fundamental error that a lot of people have made; writing bad music. I’m being deliberately simplistic here. Initially, there has to be a reason why you decide to re-imagine a story musically. Some tales or themes lend themselves to the genre. Music allows you space and time to be more reflective. At its best it lends another dimension to both character and situation. I try to use the score as a film composer would; to enhance and comment on the mood of the scene. For example, the villain of It's a Wonderful Life

How does your treatment of this show differ from your work on Spend, Spend, Spend? Particularly as it's a feel-good subject based on a classic movie.
Oddly –, and I think I may have been in a minority of one – I thought Spend was pretty feel-good. I worry though that the term “feel-good” is often thought to mean “leave your brain at home” – something you should definitely not do for either show. In some ways it is very different, simply because of the setting, but I have continued in my favoured style of keeping the drama flowing throughout from scene to scene. Spend probably has a little more knockabout comedy to it, which was brilliantly highlighted in Craig Revell Horwood’s recent production. There are more tears in It's a Wonderful Life. Millions of ‘em. We have taken a few little liberties with the storytelling – nothing to offend the movie’s myriad, die-hard aficionados – but a bit of streamlining and toughening up was inevitable and desirable.

How closely do you work with the director? We spoke at some length to the director Peter Rowe about our vision for staging the show. Happily we were largely in accord. He is absolutely brilliant and the most underrated director in the country. He wins respect quietly, not demanding it. Consequently everybody, including the writers, go out of their way to please him.

Have you always been a composer? Hermeto Pascoal, the genius Brazillian multi-instrumentalist was once asked “When did you become a musician?” He replied “On the day I was born”. I’ve been a composer for not quite as long as that. I started to take song-writing seriously when I was around 15 years old. I could play you a couple of songs from then without blushing too deeply but the musical I wrote at 19 will never be heard by anybody. It is execrable. In fact I must find it and burn it!

What other work do you do? I mostly make a living recording TV music and jingles for shows such as Harry Hill's TV Burp – he is a great friend – Ant and Dec, Al Murray and so on. Last year I wrote all the songs for Steve Coogan's UK tour and moreover ran the band on the road which was great fun. I’ve known him for ages since we did Spitting Image together and I appeared on Knowing Me Knowing You with Alan Partridge playing the role of gay bandleader, Glen Ponder. That failed to materialise into a career as an actor for me. I have recently produced an album with the fabulous female artist Rumer, who is the best singer in the country. But basically, I’m a telly whore.

Where did you train? In my parents' living room. Like so many of my generation I loved the Beatles and played guitar at an early age. I switched to piano around 14 and subsequently taught myself music theory. Now, strangely, I can write a music chart quicker than I can read it.

Financial rewards aside, do you prefer writing for the theatre, film or television? Theatre, because of the audience. You can see the whites of their eyes. Also, every night is a unique experience. I’ve certainly enjoyed such performing as I’ve done in radio because you don’t have to learn a script and the BBC always sent a car for me. I always figured that’s £20 Jonathan Ross can’t get his hands on.

What advice would you give a novice who wants to compose for the musical theatre? Seek psychiatric help.

Steve Brown was talking to Anne Morley-Priestman