How did the US naval blockade of Southern ports effect Britain durying the Am. Civil War?

Cotton was vital to British industry, and many towns in the North of England relied on cheap (slave) cotton from the Confederate states. It was even speculated early in the US Civil war that the British might intervene on the Southern side.

In fact, there was a meeting of influential cotton merchants in the north of England, during which they decided to do the "moral" thing, and side with the US against slavery in the South, regardless of the cost of cotton, and consequently, US president Abraham Lincoln wrote them a letter of thanks, and this is why there is a "Lincoln square" in Manchester, UK, with a statue of Abraham Lincoln in it.

A simple answer...the Yanks' blockade halted trade among the south, Britain, and France. Britain and France had enjoyed a strong trade relationship with the South predominantly for cotton which was stopped by the blockade. Europe then looked to Egypt for cotton, leaving the South without trade and income.

The British supported the South in hopes that they would win the war. They wanted the South to win because they believed that two nations would be easier to take back than one, after all they were still pretty p!ssed about the American Revolution and the war of 1812.

I played havoc with Britain's textile industry; they were a large importer of cotton.