Time is indeed important to mention since London nowadays is nothing like London of the late 1940s. Now, many of the peoples who have come from former Indian and African colonies populate the city.
Another important aspect of setting is the setting of time. This is quite significant in the case of the autobiographical novel, To Sir, with Love. The novel is set in the late 1940s (which is a bit different from the film which is more vague about timing). It follows the actual life of Mr. Braithwaite who, out of work in 1945, seeks employment in the school systems of London's East End. Considering London's culture in the late 1940s was a bit different from the 1960s when the movie was made, I thought the setting of time would be appropriate to mention.
The setting of Braithwaite's work is London, England. Specifically, the setting is the East End of London. This is a working class setting and Braithwaite's students reflects such a reality. The neighborhood is populated by people who work at minimal wage professions and struggle to make daily subsistence. This is reflected in the lives of the students, some of whom do not enjoy parental supervision or guidance and have been exposed to some of the darker aspects of consciousness in the modern setting at a very young age. When one of their fellow students cannot afford a funeral service after the death of their parent, the students start up a collection for their colleague. This reflects the setting in which Braithwaite has to teach, and it compels him to adopt the mentality that his best approach with his students is to teach them about life's reality that exists outside of the classroom, as opposed to teaching them abstract intellectual notions that are confined to inside it. This working class and economically challenged setting is of vital importance to the development of the work.