Spiralling high over the tarry swell of the strings, the bird-like flutes in Billy Budd suggest a freedom unimaginable to the crew of HMS Indomitable. Pressed into service, flogged into submission, teased and frustrated by the promise of battle, the sailors in David Alden's lightless, airless production of Britten's opera are adrift in a floating gulag. The sharp shadows of Expressionist cinema replace the wash of moonlight in Paul Steinberg's industrial set. Instead of timber, there is iron. Instead of the green-blue hues of the open sea, the murk of the midnight zone: the domain of Matthew Rose's Claggart.