Firstly, let's put this into context - less than 20 years after the end of WWII, two young film-makers (18 and 16 years old), with no budget made this extraordinary film. Every single frame was filmed - there is absolutely no stock footage in this at all, yet it all looks so real, from the cinematic news reels to the landscape of bombed-out Britain.
At the time, this film was labelled with controversy - the makers had intended it to be anti-fascist, but some ended up saying it was anti-Semitic. In those days, most films clearly label who are the good guys and who are the bad guys - this does not. Having recently watched "The Sorrow and the Pity" - a documentary comprised entirely of interviews with French people of all political persuasions who lived under the Nazi occupation - this was remarkably similar in the way a country buckles under. Let's remember what Europe was like during the war - a political spectrum of extremes - it was only after the war that the Allies truly came to realise the reality of the National Socialist beliefs.
So... what if the Germans had invaded immediately after Dunkirk? As the "newsreel" at the beginning says, it was a bitterly-contested fight, but eventually, weight of numbers told. Imagine if all the armies involved in Barbarossa were pitted against Britain instead...
This film has a great eye for detail and is cinematically brilliant - I was constantly wondering how the hell they managed to film Germans marching down the Mall, past St Pauls, on London sight-seeing buses, etc etc.
Get this film! It's a must see.