Wayne and Scout are natural born killers slaughtering a merry trail across North America. Everybody knows this trailer park trash. And everybody knows Bruce Delametri, director of that prime cut pulp fiction Ordinary Americans. And if there was any doubt, here is Bruce - "I stand on legs of fire" - standing up in the Dorothy Chandler Pavilion to accept his Oscar. But for the mothers of murder victims outside, it's been Bruce's night. And what do you know, he even cops off with a Playboy model at the after-show bash.

Bar an ex-wife and clingingly precocious daughter called Velvet (we can believe that at least), being Bruce Delametri is pretty good. Except that Wayne is not dumb and Wayne has an idea. Bruce's films are a bad influence, dangerous maybe. If only they could get Bruce to acknowledge culpability in their crimes, then just maybe the Mall Murderers can be saved from the Chair. Better yet, if Bruce was to confess his sins on live TV...

Popcorn has a second life on stage and it shows. Much of the second half is bound to Chez Delametri, an extended theatrical riff that so desperately wants to get intellectual but is caught-short by the cheesy comedy that ultimately disables the entire book. It's a clever short story bloated out to just under 300 pages. Oh for Will Self.

At least the book doesn't live down to his advance press about Elton coming over all Moral Majority on us, but, like the good Leftie he is, it ends up in an orgy of liberal hand-wringing. Fences are never comfortable places to sit, Benjamin. The Big Idea, you feel, actually springs from the novelist abrogating his responsibility. Wayne, in a brilliant volte-face, announces to the great American public that he will execute the assembly if the ratings computer wired into the room confirms they are all still watching. We are all guilty, "it ain't only the criminals who create a culture of violence". He's been Ben Elton. Goodnight.

Except, it's not good enough. A subject like this requires razor-edge satire, not a heavy blunt instrument. Elton's dropping of Driller Killer as shorthand for "video-nasty" on the publicity round shows him up for an interloper. He satirises Querentino well enough, all smart-talking hit men and comic violence, but that's not difficult. His insights into Hollywood are a Brit doing America, all achingly familiar plastic breasts and wannabe model-actresses. And his combining prose and screenplay is nowhere never as ingenious as he clearly thinks. Plus, when it comes to the crunch, as a novelist Elton makes a good stand-up.

What could have been biting and incisive is just wishy-washy and frequently annoying. Elton is out of his depth and by the end we are left to wonder what a real comic novelist like Carl Hiaasen might have done. What in his hands could be both funny and tragic here just ends up a bit sad.