Thought lost for more than 50 years, all six broadcast episodes of Michael Palin and Terry Jones's The Complete And Utter History Of Britain have been discovered.
Buried, miscatalogued, in ITV's archives for the whole time, the pre-Python series has been restored and is available to watch on ITVX's Premium section.
https://www.comedy.co.uk/tv/complete_utter_history_britain/
I've a real soft spot for the series: it's not quite unmitigated hysterical brilliance, but hugely entertaining and an extremely important missing link in comedy history. It was in the immediate aftermath of the series' broadcast that the Python troupe was formed, with Flying Circus debuting less than 9 months later (the very same year, 1969).
There's a good argument that this recovery is the most important find in TV so far this century.