Before I listened to this episode of In Our Time I had no idea that the American Civil War had caused hardship to so many people in Britain. The cessation of cotton imports from the Southern USA after war broke out led to the cotton mills in Lancashire shutting down, and several hundred thousand of people became unemployed. And yet the directly affected workers were still overwhelmingly on the side of the Northern USA, and for the ending of slavery.
In 1815 the British government passed a law fixing the price of grain at a higher than market price. This was the first of the Corn Laws, and it sparked rioting by those most affected - the urban poor. The laws were to last until the late 1840s, when they were finally repealed under pressure from manufacturers concerned about the effect on trade.
I knew that there was a war in 1812, but it was mixed up in my head with Napoleon & Moscow and I wasn't really sure who was fighting in the 1812 war ... but it turns out it was a war between the British & the United States of America. My lack of knowledge of it seems to be indicative of how important it actually was to the UK (as opposed to the US) but that's getting ahead of the story a bit.