It can be any genre but it has to be British. If you have more than one that's ok because I can't seem to find just one myself.
Being a fan of comedies I would have to say Monty Python's Flying Circus is my favourite as it never gets old for me I could watch them again and again.
Doctor Who is the longest running show on Television and currently one of the best.
But I can't not mention Life On Mars and Ashes To Ashes. Perfection is only word to describe these great shows.
I believe these showsto besome of the best shows in British TV history.
What are yours?