It has graced tea towels and cushions, mugs and socks, and spawned numerous Instagram accounts and coffee table books galore. Now brutalism, the once-maligned postwar architectural style of chiselled concrete forms, has finally reached Hollywood, in the form of an epic three-and-a-half-hour film that looks set to sweep the Oscars. You would think that architecture fans would be thrilled to have their subject in the limelight for a change. But they are raging.