It's on youtube, divided into 9 parts. Part 1 is here. Embedding is disabled, but the links to the other parts are there.
The Guardian says, "The film now comes across as a grimly prophetic depiction of a world out of control and on the way to extinction." Roger Ebert says, "The movie's dotty and savage; acerbic and slapstick and quintessentially British." The 1969 New York Times review didn't like it. Moria says, "If one can take the lack of plot or the film’s aimless lack of direction, there is an undeniably appealing bizarreness to its sense of humour" and describes the plot:
It is four years after World War III, which was over in 2 minutes and 28 seconds. The dazed survivors wander the ruins. A new government has been created and a Prime Minister and a monarch established. Order is then threatened as radiation causes people to start mutating into pets and items of furniture.TCM has an overview.
later that same day.... Just now seeing that Classic Sci-Fi Movies also covered this today. That site concludes: "Bottom line? BSR will not be for everyone."
2/19/2012: WTF Film calls it "One of the strangest productions ever to be made for the mainstream market" and says it's "a cynical and nonsensical post-apocalyptic black comedy that refuses to be classified no matter how many adjectives one throws at it" and describes the DVD/Blu-ray release.