The film follows a couple of days in the life of Bill Maitland, a 39-year-old Englishman who is head of small law firm in London and is tortured by his inadequacies as a lawyer, as an employer, as a husband, as a father, as a friend (he has none) and as a lover (for though women succumb quickly to him, he cannot maintain a relationship).

"[4] The Monthly Film Bulletin wrote: "The cumulative, physical impact of Nicol Williamson’s monolithic stage performance is broken by the camera’s mobility and by some obtrusively edited moments ...

Despite its precisely detailed settings – the seamy office, the tiled lavatory – and the merits of Kenneth Hodges’ austere and grainy photography, Inadmissible Evidence appears on the screen as a symbolic monologue weakened by its thin veneer of social realism and literal representation.

"[5] The New York Times wrote, "As a study of harrowing pressures that destroy a middle-aged, weak but complex human being, Inadmissible Evidence gives the satisfaction that comes from viewing a carefully crafted work ... Anthony Page, who directed the play, gives the movie's principals the focus they need.

"[6] Variety wrote, "As a play, the best thing about Inadmissible Evidence was Nicol Williamson, who brought to life the tormented, mediocre, bullying coward that John Osborne had conceived on paper.

"[7] Time Out wrote, "The main problem is the intrusive camera/editing style which reduces the original lengthy diatribes to tetchy little snippets, simultaneously cutting Osborne's magnificently theatrical anti-hero down to size: instead of being effectively inside a man's mind, we are now left outside, wondering why we should be expected to sympathise with such an unprepossessing, self-centred bore.