You have also missed the start of a slippery slope that ends up at 'The X Factor'.
Frayn's premise is simple: on stage, what happens behind the scenes is funnier than what's performed front of house. So he created the first Act of a farce-within-a-farce (called 'Nothing On'), showed it in rehearsal then revolved the set to show what was happening backstage while it was being performed. The climax of "Noises Off" is seeing the first act of 'Nothing On' performed for a third time, but full of gaffes caused by the tensions and rivalries of the cast.
The comedy is builds because the audience has seen what's happening out of view, and understands that the animosity between the characters is putting the people on stage in jeopardy.
(If ever you want proof that analysing comedy isn't funny, read the previous two paragraphs again.)
Frayn showed us things that until then we hadn't seen - indeed, weren't supposed to see: The horror when a prop is in the wrong place, the panic when a door won't open, the quick grope with the leading lady while her partner is on stage. He broke the spell - the border between reality and performance - but his brilliance was to substitute this imaginary fence with a series of stacking Russian dolls; a fake reality in a fake reality in a fake reality.
Which, some 30 years later, brings us to Simon Cowell.
Cowell makes no pretence about being anywhere near as clever as Frayn. In his press interviews, the high-waisted one always makes the point that he is a man of simple tastes, pleasures and a very grounded individual. He's a fish-and-chip man, a pop song man, a give-the-people-what-they-want man, and to hell with the critics.
But in one way, he's as clever - no, as brilliant - as Frayn. Because he saw that what happens behind the scenes, what happens before the performance, is as compelling, as dramatic, as funny as what happens 'on the night'. Indeed, by making it visible, it enriches the actual performance. We know what his contestants have been through, we've shared their pain. Even further, we start to root for them. We're bought in, even before Mr Cowell and his Syco company have released the winner's first recording. We're hooked.
And there's one further twist to the process that should make Cowell the envy of every business leader in the land:
He turned a major cost into a revenue stream.
Talent spotting is an expensive business. It takes a lot of time, a lot of travel, a lot of wasted evenings and a lot of disappointments. In short, you have to kiss a lot of frogs. X-Factor, Pop Idol, Anywhere's Got Talent all take that cost, and not only make it part of the purchase, but make it the purchase itself.
We don't just see how a finalist got to the final - we see dozens of would-be's and no-hopers (or, according to Ben Elton, "Singers, Blingers and Mingers") go through the process. That would usually be a cost to Cowell; he's turned it into revenue.
Of course, the by-product of this is that Cowell (along with his fellow judges) come out from behind that invisible wall. They become centre stage. They become as much of the act as the winning singer.
In a time of 24-hour media, of OK and Chat and Hello, of Ozzy-and-Sharon and Katie-and-Peter 'documentaries', discretion has become deeply unfashionable. You're no-one unless you have profile - whatever the personal cost.
Of course, Frayn's play isn't responsible for all this - but it was the first time that I was aware of the curtain being pulled all the way back to show warts and all; to show the mechanics of how the trick was done.
Now, the mechanics have become the show itself. There is no longer any mystery; everything is exposed.
Time, I think, to reconsider our collective hunger for transparency, and to put some things backstage, where they belong - unseen and unsaid.
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