A master of melody who could see creativity in a contract sub-clause

The biggest issue – in assessing the impact of Andrew Lloyd Webber on the world of the musical – is whether the relevant word is "responsible" or "culpable".

For his millions of fans he's a near-infallible generator of adhesive melodies. For his detractors, numerous but outnumbered, he's responsible for a sad homogenisation of musical theatre.

Where Sondheim – the other great figure of postwar musical theatre – might be regarded as a complex premier cru chablis, Lloyd Webber was always a lot closer to Blue Nun liebfraumilch – sweet to the point of sickliness but consumed in industrial quantities. And the one thing that detractors and fans would agree on is that the landscape of the postwar musical would look quite different without him.

His long domination of the West End and Broadway was not always inevitable. His early collaborations with Tim Rice were successes, with Joseph and the Amazing Technicolor Dreamcoat and Jesus Christ Superstar feeding – and helping to sustain – a temporary public appetite for scriptural song and dance. But a flop – Jeeves – came before his next huge hit, Evita, and when Cats was in production Lloyd Webber had to mortgage his house to raise part of the finance.

After that, though, he had to beat investors off with a stick, having established a reputation for bridging the gap between the traditional catchment area for musical theatre and a wider pop-buying public. One of Lloyd Webber's shrewdest tactics has been that of releasing hit songs before the production in which they feature reaches the stage – these were shows where the audience walked in humming the big numbers. And quite a lot of them had never previously bought a ticket to a musical.

He couldn't ever be accused of over-estimating that audience's intelligence. While his choice of subject has never been predictable – from Argentinian history to the Troubles in Northern Ireland – the music frequently has been.

As a composer he has been seen often as an imitator himself, rather than one of those artists who spawns imitations. What he never copied, however, was the traditional wit of the Broadway musical. Until he teamed up with Ben Elton for The Beautiful Game, laughter – at least intentional laughter – was not something generally associated with a Lloyd Webber production. Instead you could guarantee a richly orchestrated solemnity.

There was no question that the public responded to what he offered. Phantom of the Opera played in 96 cities to more than 58 million people, and earned £1.3bn in the process. It has not only grossed more than any theatrical show in history, but more than any movie, too, Lloyd Webber having worked a way round the apparently intractable drawback that you can't just run off another print of a musical if things go well. Both Cats and Starlight Express, too, were globally franchised after their London successes, an example of Lloyd Webber's genius for maximising profit. The lyricist Don Black said of him: "I've always thought that if he wasn't a composer he would have been Rupert Murdoch." He's said to relish the creative possibilities of a contractual sub-clause almost as much as that of a semi-quaver. Hardly surprising, really, that he should become the first composer to have three musicals running simultaneously in West End and on Broadway. He's likely to be the last, too.