A first class ensemble movie, 12 Angry Men has a simple but enthralling premise - twelve jurors have to sentence a young man charged with murder.

Eleven think he's guilty, but one lone juror doubts the evidence and must convince the others or the boy gets the chair.

While an acknowledged classic, Sidney Lumet's first film is an often overlooked dazzling debut - maybe because it is so accomplished, compelling and well acted - it just doesn't seem like a first film.

That Henry Fonda, the essence of old time Hollywood integrity, is the single voice of doubt makes the defendant's innocence pretty obvious but the genius is in how Fonda persuades the other jurors to question what seems an open and shut case.

Playing like a whodunit in reverse, where the murderer is apparently known from the outset but clues pile up and undo the case, 12 Angry Men plays almost entirely in the deliberation room save for a brief prologue where the judge (who also seems convinced of the defendant's guilt) charges the juror with their task, and an epilogue where two of the men's names are learned.

Reginald Rose's script (originally filmed as a teleplay) tackles the workings of a justice system where someone is innocent until proved guilty, and reveals how the prejudices, weaknesses and misplaced anger of his characters can threaten that notion.

With the precision of a grandmaster, Rose moves the jurors from one viewpoint to another as they question their reasons for believing the boy is guilty (which range from racism to wanting to catch a baseball game to just plain believing the prosecution), and has several set-pieces of knockout dialogue as the men thrash out the validity of the evidence.

For such a seemingly stagey film, 12 Angry Men is a master class in filmmaking. As the film nears its climax and tempers flare Lumet uses tighter close-ups and longer lens to blur backgrounds and focus on the actors' sweaty faces, racking up the claustrophobia.

Lumet also gives Henry Fonda one of his most iconic, yet perverse moments as he produces a switchblade similar to the murder weapon and casually flicks it open, to the shock of the other eleven men.

Fonda is the undoubted star of the film (and garbed in the most symbolic white suit in film history), but Lumet employed the cream of New York acting talent to flesh out the cast, including the coldly analytical E.G Marshall and the hate filled, tragic Lee J. Cobb.

An undisputed, endlessly watchable masterpiece, 12 Angry Men is the best courtroom drama ever made. Case closed.

Rob Daniel