It is based on the 1957 novel The Strange Case of Mr Pelham by Anthony Armstrong,[3] and is a variation on the Jekyll and Hyde story.

While driving home from his London office, Harold Pelham, a director of Freeman, Pelham & Dawson, a marine technology company, seems to undergo a sudden personality change and starts to drive both fast and recklessly, imagining himself in a sports car, and ending in a serious high-speed crash.

After he recovers from the accident Pelham notices odd things occurring and people acting strangely, and he gradually finds his life in turmoil.

Friends, colleagues and acquaintances claim to have seen him in places where he has no memory of being or doing things he can't recall, involving behaving in rash ways quite unlike his usual character.

When he gets home from work, a friend is at his house for a drink which he doesn't recall arranging, and an attractive girl at the company swimming pool casts him a knowing glance.

On a night out at the company club with his wife, he hopes to energise their relationship by indulging her request to go gambling, but he is tense and clearly not interested.

As they are about to leave he bumps into the attractive girl, who sees his wife a short distance away and says "I didn't know you were married."

When he confronts the rival firm (run by Ashton) he is reminded of three secret meetings: at the top of The Monument; in the London Planetarium; and in a boat on The Serpentine.

Distraught and unable to explain the unfolding events, he consults a psychiatrist, Dr Harris, and undergoes extended treatment in his clinic, where Harris explains that he doesn't believe Pelham is mad but perhaps was acting out of a subconscious desire to break out of his obsessively rigid lifestyle.

It was part of an overall slate of fifteen films Forbes intended to make at EMI which cost between £5-10 million.

This slate also included The Railway Children, The Breaking of Bumbo, John Quigly's The Bitter Lollipop, Dulcima, Dennis Barker's A Candidate of Promise, A Fine and Private Place, the musical The Bernado Boys, Simon Raven's The Feathers of Death, Mr. Forbush and the Penguins, The Go Between, an untitled Richard Condon script to be directed by John Bryson, and a second film from Roger Moore, based on his own story (with a script by Julian Bond) called A Question of Innocence, which Moore was to direct.

[14] It was the first film for South African actor Hildegarde Neil, who had worked with the Royal Shakespeare Company.

He was on the floor one day and I was standing there and just to take the mickey out of Basil he said 'Tell me Teddy, is he giving you enough frames to put your scissors in at the beginning and the end of a shot?'.

We aim to make them profitable in the English market and not have to depend on sales abroad- which is where many companies have come unstuck.

[23][24] Michael McNay of The Guardian wrote: "Basil Dearden handles the story professionally enough" but "this isn't my particular cup of ectoplasm.

"[26] Sight and Sound called it a "depressed psychological thriller which sets the clock back twenty years in its stolid treatment of a story about a business executive plagued by his alter ego.

"[16] Writer Wheeler Winston Dixon stated: "Slick and glossy, and looking very much the low-budget theatrical offering that it was, The Man Who Haunted Himself, despite its intriguing doppelganger theme, seems more like a television movie than anything else, and is far from Dearden’s prime work.

"[31] In 2024 The Guardian's film critic Peter Bradshaw highlighted it as "a genuinely excellent performance" by Moore.

[33] In July 1970 he Birmingham Mail reported neither Hoffman or The Man Who Haunted Himself "have burnt up any box office tills; nor have they shown signs of getting critical raves.

"[34] Alexander Walker later argued The Man Who Haunted Himself, Hoffman and And Now the Darkness "were all films obviously rushed into production to get the studio ship-shape again: Forbes couldn’t afford the luxury of waiting for the off-beat, or chancing an untested project.

had then no West End ‘showcase’ cinema — and coincided with the World Cup football play-offs, a heat wave, and a general election.

A new HD restoration from the original film elements was released in a dual-format package on 24 June 2013 by Network.

Special features include - 34 minute music suite of Michael J. Lewis's original score; a commentary track recorded in 2005, featuring Roger Moore and Bryan Forbes; the original theatrical trailer; four image galleries, including storyboards; and promotional material in PDF format for reading on a PC.