One of best new radio programmes is Sue McGregor's Reunion on BBC Radio 4, in which participants on a great project or chapter of political or social history reuinite round a table to discuss the event in hindsight.

We've had two great showbiz episodes: first, the reunion of some of the Liverpool Everyman Theatre in the early 1970s and, just the other week, another Liverpool trip down memory lane on Alan Bleasdale's Boys From the Black Stuff on Channel 4.

Yesterday's edition was devoted to Les Miserables, and didn't dodge any dissent or rancour. First up, Michael Billington (not in the sudio, on tape) sniffily diagnosed Les Mis as part of a Thatcherite global musical theatre ecology, a point more subtly appropriated (in the studio) by co-director John Caird as evidence of people's hunger for compassion and love in a "me first, greed is good" society.

Then there was Cameron Mackintosh and Caird disagreeing about politics in China, and the show's standing there; which opened up the way for Caird to express his and Trevor Nunn's hurt at not being invited to re-visit the show for the 25th anniversary touring production that played at the Barbican (which was, in effect, a pale re-tread of the original, not a re-think).

Cameron replied that, like any great show, Les Mis deserved a creative makeover. To which Caird responded by suggesting a change of producer, too. Ouch.

The critics came in for some flak, and Cameron and Caird were at least agreed on this point: that there is an innate critical snobbery about musicals that just won't go away. Lyricist Herbert Kretzmer was too pained to name the writer who, in the Spectator only the other week, said that Les Mis was a case of the Emperor's New Clothes.

And they all rounded on the Observer critic of the day (my predecessor there, Michael Ratcliffe, though they remembered him, for some reason, as "Michael Hastings" the playwright) who complained about the show for several weeks running.

Fascinatingly, Kretzmer recalled he was stuck for a lyric on "Bring Him Home," with its clutches of three rising notes punctuated by long pauses, until Caird casually let slip, as he left Herbie's house in the small hours after a long session, "Sounds like a prayer to me."

That, of course, is the show's greatest number, though, as Cameron said, there was never a hit song until Susan Boyle sang "I Dreamed a Dream" on a TV talent show nearly thirty years after the premiere.  

And Michael Ball, the first Marius, aged just 22, said that the show not only changed his life but also drove him into a major nervous breakdown from which he happily recovered after nine months away. 

When Cameron first decided on Trevor Nunn as the director, Nunn had two conditions on which he absolutely insisted: that John Caird came on board as his co-director; and that they would present the musical first at the RSC.

This led to all sorts of rumbles and disputes even within the company, but the fact is that the RSC probably survived in the 1980s because of the annual income of £1m a year from Les Mis. And that pioneering association between the subsidised and commercial sectors is now an everyday fact of life (for good, and for bad).

No dissent of any kind last night at the fourth annual Knight of Illumination Awards sponsored by Italian lighting industry suppliers Clay Paky in the Hyde Park Hilton, where Bruno Poet was dubbed on both shoulders for his sensational work on the National's Frankenstein, and Hugh Vanstone ennobled for his colourful, scene clinching contribution to The Wizard of Oz at the Palladium.

But the night's, and the Knights', standing ovation went to Richard Pilbrow, whose creative lifetime as a designer, theatre consultant and producer, stretching from the West End in the 1950s through to the new National Theatre and beyond, was resoundingly recognised by his peers.

In 1957 he founded the first ever lighting company, Theatre Projects, and has tripped the light fantastic ever since, though he said, "when I started, nobody wanted me... and the pay's still shit!"

He's a wonderful man, Pilbrow, and I can't wait to read his new book. He now lives in Connecticut. Why? "I love it there, and I left this country when they kept on building such bad theatres." I listed a few: Chichester, the Birmingham Rep, Nottingham Playhouse, the National (Olivier and Lyttelton)... he didn't demur.

What theatres does he like? The Sheffield Crucible and the Cottesloe. That's about the size of it. His first shows as co-producer were A Funny Thing Happened on the Way to the Forum and She Loves Me, but I think the one that meant most to him was Company by George Furth and Stephen Sondheim. He said he will never forget the night it opened, and the audience went stir crazy. I saw that first London production in 1972 three times: it still only ran for a year. 

Pilbrow said that when he joined the Association of Lighting Designers he was the only member. Today, there are two thousand, working right across the entertainment industry in theatre, dance, opera, television and rock concerts.

London has the best theatre, and Broadway used to have the best theatre technicians. Now I suspect we have the best of both worlds, and much of this reputation is down to one of our truly great unsung heroes: the prodigious Pilbrow.