My father was a film-maker. He always said he wanted to go like Humphrey Jennings, the legendary director who stepped backwards over a cliff while framing a better shot.
Science fiction is never about the future, in the same way history is rarely about the past: they're both parable formats for examining or commenting on the present.
Beautifully shot, impeccably paced, it was a clear, unrelenting look at the National Trust, its friends and enemies, and it makes you want to burn your passport and beg the Luftwaffe to have another go.