Peter Cook could have people rolling on the floor at cocktail parties, but he didn't make stuff to last.
He was a japester, not an artist.
The sketch show with Dudley Moore (Not Only, But Also) was his best shot, but it's only a sketch show- a slightly riskier Morecambe and Wise. It doesn't break new ground like The Goon Show or Monty Python.
Putting on a cap and muffler and a proletarian accent- it's not that clever. It's Oxbridge humour. Oh my dear, aren't working-class people a scream!
Cook did funny voices. Peter Sellers did them better. Cook doing funny voices is just Cook doing funny voices- Sellers as Strangelove or Quilty is a window onto the apocalypse.
Lots of comedians drink. Keaton drank, Fields drank, Hancock drank. They all managed to reel off some deathless stuff before the drink got to them. Cook didn't.
Cook didn't progress beyond his beginnings. In the last set of interviews with Clive Anderson he's still the clever undergraduate cheeking his elders and betters. You laugh out of respect. It's like a Paul McCartney gig. Paul has been crap for thirty years, but you sit up and pay attention because he used to be a Beatle.
Cook was a brilliant young man. After which he noodled and frittered and guested.