Complex sentence: Manchester was, at the time, the hub of the world's textile manufacturing industry, and had a high population of factory workers, who were disadvantaged by the Corn Laws, the protectionist policy that imposed tariffs on imported wheat and increased the price of food.
Split into simpler sentences: Manchester was, at the time, the hub of the world's textile manufacturing industry. Because of this it had a high population of factory workers, who were being disadvantaged by the Corn Laws, the protectionist policy that imposed tariffs on imported wheat and therefore increased the price of food.