By the time of the partial collapse of the 23-storey Ronan Point tower block due to a natural gas explosion in 1968, local authorities were waking up to the scale of the deficencies and the cost of making safe the 750,000 flats built during the ten year boom. It then emerged that up to 6 million people were living in poorly constructed or dangerous system-built housing erected in the 1920s, 1930s and 1950s and beyond. Ironically, many of the proposed expensive remedial systems were found to be similarly untried, untested and unfit for purpose, and in some cases offered by the same construction industry chiefs previously vending the very inadequate building systems that now needed remedying. Fans of Adam Curtis's work should note that, as an early Curtis production, this solid investigative documentary lacks the narrative thread and unique voice that characterises his later work, but favourite themes are present, such as the collusion of the powerful and opportune, and the inability to learn from past lessons.