Jon Spira has, undoubtedly, made one of the best historic accounts of; modern British filmmaking and the British film industry. One could argue that the selection of covered films is biased, but that is way within the directors prerogative - it is NOT titled; "A Complete Account of British Film..." and the choice is, in itself, interesting.
Reel Britannia is, almost, exactly what it says on the box - and the ingredients are pretty tasty. In all likelihood, however knowledgeable you are, there will be morsels of new trivia to pick up along the way - and ample occasions to brush up on old knowledge.
For once the recommendation is pretty clear:
If you have a passion for film in general and British film in particular - this is the definitive "must see". (If you have neither chances are you will hit "stop" before the end of the first episode).
Nick Helm's, excellent, dry humorous narration steers Reel Britannia into a natural flow and lifts it from; highly informative to highly enjoyable.
I short; Reel Britannia is a long awaited box of cinematic treats.