It was, however, Adam Smith and other English classical economists who further developed and perfected the economic doctrines of the Physocrates. In his book, The Wealth of Nations (1776), Adam Smith presented them in a scientific form, which became widely popular. He denounced the laws which restricted trade and free exchange of commodities and free employment of workers by the employers.
He asserted that the traders, employers and workers knew their interest better than the government and therefore, their relations should not be regulated by it. In other words, there should be free competition among them.
The State should confine itself to protecting private property, the right of contract and guarantee freedom of competition and self-interest. So great was the influence of laissez-faire that all European Governments adopted it in their policies and legislation during 1820-80