The battle for the battle of Britain
This was a documentary made of the making of the film.
It was presented by Michael Caine and was a very interesting and informative look at behind the scenes as to how the movie was put together.
I've seen it once on YouTube, but it seems to have disappeared off there.
If you're at all interested in how they made this classic film, try and find this.
Hopefully one day it'll find its way back onto YouTube.