How do governments promote competition in the marketplace?

Government promotes competition in market place by putting in place and enforcing anti-trust legislation, by engaging in trade with other countries of the world [global trade], by supporting new businesses that are just coming up. Anti- trust legislation are put in place by the government in order to discourage development of monopoly in the market place. 

from the conditions of the working class in england by friedrich engels,the main idea is :

manchester's leaders hoped to oppress its working class to benefit factory owners.