1. Society was still very divided
2. The Industrial Revolution and rise in mass production of goods in factories meant that the middle class began to be able to acquire more wealth through owning private businesses
3. Owning more money and the desire to ape the social ladder, meant that the social hierarchies became slightly more fluid
4. Men like Mr Birling, who we will read about in 'An Inspector Calls', desired to climb the ladder and became part of an emerging upper middle class
5. Gerald Croft, on the other hand, had inherited wealth from his parents, making him part of the upper class