Actually, The Sky At Night isn't Britain's longest-running TV show - that honour falls to "Panorama", which launched in November 1953. (That's leaving out the News and Weather, obviously.)
What about Blue Peter!!! I know it's not as old as Sky At Night, but surely that's gotta be near!
And the news! Who can forget! THE NEWS!!! is the longest running programme!
Well, the world's longest running chat show is The Late Late Show on RTE, the state broadcaster in Ireland. It's been on the go since 1962 - but it seems even longer.