OP, if you're at all interested in history, you might like to read up on Free Trade and British politics in the 19th and early 20th century. Starting with the Corn Laws and Sir Robert Peel. (Which anyone old enough to have done O level history will no doubt remember!)
There was a divide between producers, who wanted tariffs on imported goods to protect them from foreign competition, and consumers, who benefitted from having access to a wider range of often cheaper imported goods. Tariffs, being taxes on imports, also raised money for the government.
This particularly applied to food, so it became a hugely emotive and divisive issue.
The issue of Free Trade twice caused a major split in the Conservative party; what we're seeing now is (so far) mild in comparison.
The counter argument to Protectionists, as anti-FreeTraders were called, was that if we imposed tariffs on goods imported from, say, the USA, they'd do the same to us, making it more difficult for our producers to export to them.
Free Trade was the dominant view in the second half of the 19th century. Britain negotiated Free Trade agreements with most of its trading partners. Then towards the end of the century there were increasing demands from producers for Protectionist policies.
That's a very simplified account. There's a lot more to it than that, but this would become an (even more) extended essay. Congratulations to anyone who made it this far!
(I teach history, in case you hadn't guessed!)