Now, thanks to Vanessa Redgrave (who retrieved, and pressed the claims of, this unperformed 1938 script) and to Trevor Nunn who gives it a viscerally powerful premier production, Not About Nightingales necessitates a rethink. Everything on Richard Hoover's admirably confrontational traverse design (cells at one end; office of corrupt pig of a governor at the other) is bled of colour: even the Stars and Stripes droops ashenly. Shades of grey are largely confined to the set, however, for, in its principled anger, the play trades in the black and white of melodrama.
Nightingales shows you a Williams fighting for right and, to a fascinatingly limited extent, fighting his own lyric instincts. The very title is an index of this, the explicit painful rejection of the Keatsian for angry eye-witness reportage by the play's conscience figure and surrogate dramatist, Canary Jim. Performed with an edgy brilliance by Finbar Lynch, Jim is a self-educated literary con, sweating on the parole he has earned by being the governor's stool pigeon and falsely presenting prison as "the door to opportunity" in the in-house magazine. He's playing a double game: surface collusion is the price for collecting documentary material on the atrocities committed by authority. Once out, he can reveal all and cause heads to roll.
A subtler play might have depicted an idealist more contaminated than Jim is by his tactical collaborator role. It might also have explored at greater depth the parallels between the totalitarian governor - whose monstrous, toying sadism and red-neck sentimentalism are magnificently captured by Corin Redgrave - and James Black's seethingly pugnacious Butch, a terrorising con who likens himself to Mussolini and Hitler, opposes Jim's subterfuge strategy for reform and bullies the men into a face-off they can't hope to win.
Justifying these apparent simplifications, though, is the sceptre of the Depression, seen not just in the references to Thirties dictators, and the reason many of these cons resorted to crime, but in the moral dilemma of the new secretary (a splendidly sympathetic Sherri Parker Lee), torn between truth and dread of the sack. With its jets of steam hissing murderously into the windowless cell, and its hard-to-watch violence, Nunn's production builds up a pressure cooker atmosphere.
Much more than a historical curiosity - if also less than a masterpiece - Nightingales is another coup for the new National regime.