Was the Industrial Revolution the period of great free-trade thinkers like Adam Smith and David Hume? Yes.
Was it a period of free trade? No.
One of the things that has struck me in my study of the Industrial Revolution (1750 to 1850) is how much protection the British government gave to various industries through tariffs or bans on imports.
Let’s start with wool, once Great Britain’s largest industry. From the mid-1600s, the woolen-cloth industry had kept its raw material prices low through a ban on the export of raw wool. Then at the end of the century calicoes (printed cottons from India) became quite popular. The wool industry responded by getting Parliament to ban imports of calicoes in 1700.
The law kept out Indian cotton but it opened the door to homemade British cottons! First, British companies began printing imported cloth to create calicoes; then they started producing the cloth itself.