I back the suggestions of The IT Crowd, Spaced and Black Books (I have the special edition boxed sets for the last two)
Ahhhh Dani, Chelmsford 123. I thought I was the only person who remembered that. I watched it primarily because it had so many of the Radio Active crew. And then carried on watching it because I fell in love with Rory McGrath. I still wouldn't kick him out of bed. Completely filthy, I love it.
Ibs you might like to check out The Young Ones. Very dated now, but the mixture of profanity and violence is still funny in an adolescent and particularly British way.
And I can't let this post go by without pushing my heroes - The League of Gentlemen. I'll let someone else explain them so I don't sound like too much of a fan-girl:
At times genuinely moving, at others so profoundly disturbing and shocking that it transcends traditional comedy, most of the time The League of Gentlemen is just extremely funny, biting and brilliantly, dramatically written - the classiest sketch-based format written in recent broadcasting history.
Starting as a revue format at Edinburgh and then vaulting onto radio, The League of Gentlemen is a sketch show, although it is also a sitcom - particularly in its television guise.
In the village of Royston Vasey, various characters mostly played by Gatiss, Pemberton and Shearsmith inhabit a dark world of secrets and offhand depravity.
Oh and if you can get hold of it - Funland. Again, surreal, violent, funny and dealing with themes of pornography, taxidermy, incest and other fun family issues. Co-written by Jeremy Dyson and featuring Mark Gatiss (both of The League as above).
BTW Mark Gatiss is a Who writer and performer - he's written a number of Who books and three (I think) Dr Who episodes. He's also appeared in one, as has Steve Pemberton, another of the League, as was the man who owned the library world in an episode just a few weeks ago.
Mark's working on a series called Clone, which hasn't had good feedback from audience members during filming, but I'll give it a go anyway. Steve and Reece are filming a series called Psychoville (the Japanese title for The League of Gentlemen series) this October.
Oh and how could I forget? If you manage to catch Benidorm! It's another filthy gorgeous sitcom. Might lose a little in translation, being about Brits abroad, but I should think most of it will be readily accessible. I love it because of the quality of the writing and the superb timing of the excellent ensemble cast. And because Steve Pemberton spends most of it in shorts :yum: Also notable for the appearance of Johnny Vegas, very funny man.