The other Lloyd Webber: Andrew's father William has always been overshadowed by his son's musical blockbusters

Well known as a musical academic, professor at the Royal College of Music and, from 1964, director of the London College of Music, William Lloyd Webber (1914-1982) nevertheless left his true vocation, composition, largely unfulfilled. His younger son, the cellist Julian Lloyd Webber, describes him as not so much embittered as disappointed and extremely private. "He would often see celebrated conductor colleagues at the Royal College," he says, "but told none of them he was a composer."

His musical style is exceptionally direct: "He had a way of putting a lot into a very short space of time," Julian suggests. His output includes church music, chamber works, songs, a Serenade for Strings and more – yet despite the music's audible appeal, most remains virtually unknown, perhaps because he wrote no flagship symphony or concerto.

Over the years, Julian has unearthed, published and recorded some key works; but the father remains far overshadowed by his elder son's blockbuster musicals. It is almost as if he sacrificed his own creativity for his children.

William Lloyd Webber's father was a London plumber who happened to adore organ music. By the age of 14, William was giving organ recitals himself. He won a scholarship to the Royal College of Music, where he studied composition with Ralph Vaughan Williams, and gradually built a career as organist and composer until the Second World War intervened.

So, too, did marriage, family and musical zeitgeist. In 1942, William married Jean Hermione Johnstone, a violinist whom he had met at the Royal College. Andrew and Julian were born respectively in 1948 and 1951. The postwar years were a tough time to be a struggling musician with a young family.

"I think he simply had to make some money," says Julian, "and composition wasn't doing it for him." Andrew has been quoted as saying he believed his father would have liked to write film scores, but was discouraged by his own father who thought this an inferior path.

Indeed, William's music proved out of step with its era. The 12-tone serialist system had rendered tonal, romantic music such as his old-fashioned and often critically reviled. Together with his unwillingness to champion his own works, this proved destructive. In the year Andrew was born, William wrote his most substantial (10 minutes long) orchestral work, Aurora, depicting the sensual goddess of dawn. "He sent it to the conductor Sir Malcolm Sargent," Julian recounts, "but received no reply.

This kind of thing happens all the time, of course – but he assumed it meant Sargent didn't like it and he never sent it to anybody else, ever again. Malcolm Arnold, whose music was similarly out of step, went on composing despite horrible reviews. He kept at it. My father didn't."

Julian paints a portrait of a quiet man who knew much but spoke little and remained emotionally distant. "He was strangely remote," he says. "He would come to my concerts and Andrew's shows, but he wouldn't say much afterwards. That kept us on our toes. There was always a sense that things had to be excellent, or else were a complete waste of time."

Andrew has said that he felt "closer to my grandmother than I was to either of my parents" and that while their mother enthusiastically encouraged gifted youngsters from outside the family, "there were moments when we felt that nobody was really interested in us".

Keys to success: Andrew and Julian Lloyd Webber (Rex Features)
There was no doubting their father's musical perceptiveness, though. "Once Andrew and I as teenagers were listening to the Beach Boys, who were new and innovative at the time, and we heard an amazing chord in 'When I Grow Up to Be a Man'. We were at the piano trying to work out what it was, but we just couldn't get it. We went to our father as last resort, as he wasn't a big pop fan, and found him mixing cocktails. He used to make unbelievably potent cocktails – sometimes people would ask for water, he'd pour it over the ice he'd used to mix the drinks, and they'd go reeling out. Anyway, he went to the piano, played the chord immediately, and told us exactly what it was."

Andrew's music soon took a direction of its own. "I think our father was amazingly impressed by Andrew," says Julian, "especially as Jesus Christ Superstar was on a big scale and Andrew was very young when he wrote it." Preparing Cats in 1981, Julian recalls: "Andrew felt there was something missing and he came up with 'Memory' literally a few days before opening night. He came round to play it to us all. Our father said simply: 'It sounds like a million dollars.'"

Yet in other respects father and son could be musically related. "His music certainly made an impact on Andrew," says Julian. "I can hear it most clearly in Love Never Dies – the lush romanticism of it." Andrew wrote his Requiem (1985) in memory of his father.

Sure enough, William's romanticism might be the key to his compositional impulse. The violinist Tasmin Little has recorded his Benedictus, a wedding gift from William to Jean: "It is so heartfelt that it's hard to imagine a greater musical love-gift, except for Wagner's Siegfried Idyll," she says.

And in an unexpected postscript, he returned to composing in 1979 to produce an utterly gorgeous choral work, the Missa Sanctae Mariae Magdalenae. "The stimulus was that he met a girl named Justine Bax," says Julian. "And I think he fell in love."

Julian heads a concert of his father's works at St Martin-in-the-Fields on the centenary itself, and festivals are planning treats, including Barnes this spring. Yet still he dreams of hearing a fine performance of Aurora. "Sometimes I'd see him at 2am, listening in tears to its one then-existing recording," he says. "I kept out of the way."

A Celebration of William Lloyd Webber, St Martin-in-the-Fields, London WC1 (020 7766 1100) 11 March