When I visited the Ballincollig Gunpowder Mill (the Royal Gunpowder Mill) outside of Cork, Ireland, I asked if the gunpowder made there was exported to the States during the US Civil War.

The answer was "Yes, mostly to the South, but some to the North."

Medical supplies, including quinine and other medicines, were exported to the South along with British Pattern 1853 Enfield rifled muskets. The total number of Enfields sent over to both sides was about 900,000.

Yes, there was British support for the Confederacy. Some was due to the idea of the Blockade, which did not permit ANY ships to enter or leave the Southern harbors. Normally, the interdiction of medical and food supplies would have been against the "laws of war" -- but the Union took the position throughout the War that the Confederacy was not a separate country and hence any blockade was proper and in keeping with the "laws of war." Note that the United States never declared war on the Confederacy, reasoning that a country cannot declare war on itself.