The city of London was a magnet for the migrant populations due to the job opportunities provided by its dockyards and industries. By 1750, one out of every nine people of England and Wales lived in London. So, the population of London kept expanding through the eighteenth and nineteenth centuries.
During the First World War, London began manufacturing motor cars and electrical goods. This increased the number of large factories, which in turn increased the number of people coming to the city in search of work.