1970

One fateful day in the late 60s, comedy writer Jimmy Perry decided to create a sitcom based on his own teenage experiences in the Home Guard. The concept was a stroke of genius, which is more than can be said for his chosen title: The Fighting Tigers. Luckily, someone at the BBC decided to de-rubbishify the name by changing it to Dad's Army. Running for much of the 70s, it gave us the iconic Captain Mainwaring and remains one of the greatest sitcoms ever made.

And speaking of sheer brilliance, the year 1970 saw the Monty Python lot come up with some of their defining sketches. The Ministry of Silly Walks made the most of John Cleese's gangly frame (Peter Crouch would be perfect for a remake), and Michael Palin constantly burst in as the Spanish Inquisition. Nobody expects them, you know.

1971

Morecambe and Wise seem as 70s as space hoppers and Black Forest gateau. Which actually misses out the fact that the great comic duo had already been on telly for decades before then. They even interviewed the Beatles in the early 60s, with Eric Morecambe and John Lennon exchanging a flurry of wisecracks.

Still, there's no denying that it was the 1970s made Eric and Ernie light entertainment gods. Just take the Christmas show of 1971, in which we saw Eric Morecambe grandly attempt a classical piano concerto. And by "attempt" we mean "thoroughly mangle". But – as Eric immortally put it – he did play all the right notes. Just not necessarily in the right order.

1972

It's great when family members hate each other. Well, not so much in real life, but in sitcoms it's gold. And there was always plenty of contempt to go round in Steptoe and Son, that darkly comic series about a rag-and-bone man and his scowling nightmare of a father. The battle lines were literally drawn in 1972 when Harold divided the house to get away from wizened old Albert.

Of course, it probably helped that the two stars didn't actually like each other much in real life. No such problem was encountered by The Goodies, the three chums whose brand of bonkers surrealism reached crazed heights with 1972's "Kitten Kong" – an episode about a giant cat destroying bits of London (and Michael Aspel). And here's a bit of trivia: the Goodies (aka Bill Oddie, Graeme Garden, and Tim Brooke-Taylor) were mates with John Cleese and Eric Idle when they were students at Cambridge.

1973

In 1973, a new breed of stupid was unleashed on Britain's TV screens. A breed of stupid that wouldn't be surpassed until Mr Bean came along years later. We speak of course of Frank Spencer and Some Mothers Do Ave Em. Everything about this sitcom became iconic overnight, from Frank's beret and trenchcoat to his catchphrase ("Ooh Betty!") to that weirdly minimalist theme tune (which was actually a piccolo spelling out the show's title in Morse code).

Rather more sensible was Whatever Happened to the Likely Lads, a rare example of a sitcom sequel that's much better than the original. It was the Men Behaving Badly of its day, but with added dollops of class struggle and pathos. It's just a shame that James Bolam and Rodney Bewes had a huge fall out shortly after the show ended. Volatile business, comedy.