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I didn't see "Parkinson at 50", but I suppose he was paid to introduce it, so it must count as part of his TV career and therefore the reference to seven decades can be justified, even though "Parkinson at 50" was just a rehash of his old shows, introduced by him and his son. The title of that programme was a dead liberty, though. True, it was broadcast 50 years after the first Parkinson programme, but that show ended in 2007 (with a gap of 16 years from 1982 to 1998), yet there was an implication that the show had been going for 50 years.