Why was Liverpool involved in the American Civil War?

Old photo of the Liverpool waterfront with sailing ships in the river

Liverpool Panorama c1860, showing how the waterfront looked at the time of the American Civil War. 

The American Civil War (1861-1865) was caused when eleven Southern states seceded (or broke away) from the United States, 'the Union', and formed the Confederate States of America, 'the Confederacy'. It began on 12 April 1861, when Confederate forces attacked the Union held Fort Sumter in South Carolina. Although Britain was officially neutral, Liverpool, the Wirral and Lancashire had strong political and financial connections with the Confederacy.

Cotton was Liverpool's most important cargo in the 19th century. Raw cotton, produced by the labour of enslaved Africans in the Southern American States, was imported through Liverpool for Lancashire mills. Once the Northern Union ships began a blockade of Southern ports on 16 April 1861, this trade declined with serious effects in Liverpool and Lancashire, where a 'cotton famine' resulted in mill closures and mass unemployment in 1862-1863.