The National Health or Nurse Norton's Affair began as a play written by Peter Nichols (of A Day in the Death of Joe Egg fame) who from his play wrote this film script. The play was originally performed at The National Theatre at The Old Vic 16th October 1969 directed by Michael Blakemore who, with a brilliant cast, injected the dull subject matter with brilliant touches of humour totally lacking in this film production, particularly Nurse sweet, originally performed brilliantly by (sexy and super-efficient) Anna Carteret on stage and in a mediocre (plain Jane) fashion by Lynn Redgrave in the film. The only two members of the original production to join the cast of the film were Jim Dale and Gillian Barge. Subsequently the production opened in America and due to its theatre success caught the attention of filmmakers.
I have no idea what Peter Nicolls thought of the film but Jack Gold made a mess of it, presumably not wishing to duplicate Blakemore's direction but instead casting it with known stars who managed to miss all the subtlety of the original production. As another reviewer commented, the film falls into the trap of so many British films: that of staying faithful to its previous incarnation in another medium. Well I totally disagree. Dale's contribution lifts the film whenever he appears. It is the original theatre production that generated the success. It can not be assumed that success can be lifted and transformed into a film without some serious attention to detail - what made the success, what made it tick. What made it tick as totally missing in Jack Gold's treatment of the subject - hence the negative reception and our loss. This could have been a little gem of a movie.