What is a social class?

Social class is a way of categorising people according to certain qualities they may have, or conditions in their life. In the United Kingdom this can be things like your parents' jobs, what kind of education you receive, or what kind of connections you or your family have in society. There are three main classes in British society and they are upper class, middle class, and working class. Upper class can be seen as the small amount of people who have a lot of influence and money . Middle class people tend to have been well-educated and have jobs such as doctors, solicitors, or managers. There are different types of working class people for example skilled workers and unskilled workers. These people often do jobs that do not require a university degree.
A lot of sociologists have different opinions on the class system and whether they think it's fair or not. Some believe it is necessary for the society to work well. Others believe a person can move through them and they aren't the best way to talk about our population. Do you think it's fair?