In Chapter 5 of To Sir with Love, the narrator describes his difficulties in finding a job. His problem is neither lack of qualifications nor lack of experience; rather, his main problem is his black skin.
The first job interview the narrator describes is at an electrical firm in Dagenham which is looking for technicians. The interviewer rejects the application because, he says, Braithwaite is much better educated and better-dressed than the other employees. "They might resent the posh way you speak," he says.
After this rejection, Braithwaite begins to develop a hostile, "cancerous" attitude toward British society.
His life changes when he by chance meets an old man in St. James's Park. The old man listens sympathetically to Braithwaite's problems. He then suggests that he look into becoming a teacher. He specifically recommends that Braithwaite look for employment in London's East End neighborhood, which was known as "rather a tough area."
Braithwaite is interviewed by the Ministry of Education, is hired, and is ordered to report to the Greenslade School.
The rest, they say, is history.