This is a unique glimpse of London office life of 1/2 century ago. I focuses on this guy who is hired to do bookkeeping and keeps telling his boss "I prefer no to" do anything he's asked. Spoilers ahead.
We find out he's homeless and living in the office, and the boss, the world's most conciliatory one finally fires him, but he still doesn't leave the office, so the boss moves the company to another building. Eventually the police take hime to a mental home where he dies due to refusing to eat.
I thought it was well done, comical, and a good glimpse of 1970 London, showing the street scenes, office technology of the time, etc. And it's got a weird psychological twist that was part of the creative explosion happening at the time. Based on the Herman Melville story.