Brooklyn-born crime boss ‘Crazy’ Joey Gallo was so preoccupied with his image, he watched the movie Kiss of Death fourteen times to study Richard Widmark’s manic giggle as he pushes a wheelchair-bound old woman down a flight of stairs. I remembered this when a young woman in Manhattan was telling me about some emotional upset or other during the glory days of Sex and the City.

‘You know what I always wonder?’ she said. ‘How would Carrie Bradshaw be handling this?’

This brought home the way television has largely replaced movies as a mapmaker for our lives. It also seems relevant when contemplating the underlying factors that distinguish British television from American television, from the best on show to the gag-reflex awful.

During its early decades British television, like the rest of popular culture in this tight little island, reflected the world around it. Whether milked for laughs or melodramatised, shows of the calibre of Steptoe and Son and Upstairs Downstairs, and characters like Alf Garnett and Soames Forsyte, were founded on longstanding national, social and economic realities. In the huge, shifting demographic of the United States, however, popular culture has always had a mighty hand in actually creating the world that absorbs it. This was true in the day of the dime novels and tabloid journalism that produced Billy the Kid and Buffalo Bill. And it’s true today, with FBI tapes recording mobsters discussing The Sopranos. This distinction has been much broken down, though, by the ping-ponging of Anglo-American cultural relations: as with the Brits inventing Pop Art, then the Americans doing it more coolly, more famously; or the way New York came up with Punk rock, then along came Malcolm McLaren to scope the acts at New York’s CBGB. Television has been a two-way highway in this process. The tangled family tree of sophisticated TV humour bears witness to this. Rowan and Martin’s Laugh-In broke the ground for a sort of vernacular surrealism. That Was The Week That Was imported satire. These two begat Saturday Night Live, Monty Python, National Lampoon, Spitting Image, and much more. It used to be a commonplace Brit prejudice to say that our ingenuous American cousins don’t ‘get’ irony. Indeed, you can still hear this today, if only from crusty folk who have never caught, say, David Letterman, a talk show so drenched with irony that it could drown a litter of kittens. Then there’s The Daily Show.

The half-hour The Daily Show, which opened in 1996 with Craig Kilborn, who was replaced by Jon Stewart a couple of years later, has a clear lineage. It began with David Frost. Then came SNL’s Weekend Update, of which the original anchor was Chevy Chase, HBO’s Not Necessarily the News and Channel 4’s The Eleven O’Clock Show. And it confirms the role of American TV in shaping popular culture, rather than reflecting it, that whereas David Frost could have been confident that his viewers would be familiar with his source material – newscasts, the papers – a Pew Research Center poll in 2004 discovered that 21 per cent of Americans between 19 and 28 cited the trenchant humour of The Daily Show and Saturday Night Live as their principal source of political news.