A couple of months after Peeping Tom opened in cinemas, its esteemed British director, Michael Powell, told an interviewer: "I don't think of it as just a horror film at all - I tried to go beyond the ordinary horror film of unexplained monsters, and instead show why one human being should behave in this extraordinary way - it's a story of a human being, first and foremost."

Peeping Tom is incredibly effective, and its complex portrayal of a sadistic serial killer was groundbreaking. Unfortunately, for its director, too groundbreaking; far too effective for the film critics of 1960 to handle. They were horrified, and slaughtered it, laying into Powell and calling for the film to be literally flushed down the toilet. The distributor swiftly removed it from cinemas, bringing an abrupt end to the career of a great director who had enjoyed major success with the likes of A Matter Of Life And Death and The Red Shoes. He went to live in Australia, and Peeping Tom was left to rot... for the time being.

Half a century later, it's still immensely powerful, a unique, claustrophobic character study. Austrian actor Karlheinz Böhm is still magnetic as Mark Lewis, an awkward camera operator who becomes almost cripplingly shy around women. Well, the ones he likes, anyway. Others are killed with an extendable knife he has attached to his film camera; he's not very polite with them, murdering with no emotion, bar the thrilling sexual gratification he gets from capturing their terror on film as his blade pierces them.

It's these Terminator-esque first-person sequences that particularly upset critics, who were irate that Peeping Tom made voyeurs of all who viewed it. But Powell was also attracted to the film's notion of filmmaker as voyeur, or, as one character in the film says, "the morbid urge to gaze"; the director endured further criticism by casting himself as the killer's father in the scenes that explain Lewis' backstory, which involve dad psychologically experimenting on his young son by scaring him in the middle of the night and filming his terrified reaction.

Everything changed in 1980, when Peeping Tom fan Martin Scorsese befriended Powell and supported a re-release of the film, which was at last critically lauded. Later still, one of those who had contributed to its downfall publicly repented: In 1960, Dilys Powell of The Sunday Times wrote that Powell "cannot wash his hands of responsibility for this essentially vicious film". When it was show on TV in 1994, she awarded it Film Of The Week, writing: "I hated the piece and, together with a great many other British critics, said so. Today, I find I am convinced that it is a masterpiece. If in some afterlife conversation is permitted, I shall think it my duty to seek out Michael Powell and apologise. Something more than a change of taste must exist."

Peeping Tom has dated, but in a great way - it's a fantastic document of 1960s Soho, which looks very appealing on this new DVD. The special edition includes an informative commentary from film critic Ian Christie, a new 20-minute featurette with good contributions from Scorsese, Böhm and others, and (puzzlingly) a 25-minute French featurette. You must buy it.