We have quite a few threads on foreign relations during the Civil War and British govermental views and actions . Any mod should help you find them if you send a private message.
The U.K. along with most of West Europe were quote " neutral" but in reality sold weapons and lots of them at that to both sides. In particular the U.K. , France, Belgium and Austria.
The British openly built smuggling ships in particular in Clyde, Scotland. British and French Islands in the Carribean were chock full of blockade runners. The Spanish allowed blockade runners to use Havana aa well. Montomoros, Mexico was a major smuggling port until the Union captured Brownsville, Texas.
The Confederate Naval Raiders the Shenandoah and Alabama were British ships with British sailors and British cannon but were not part of the Royal Navy.
European countries granted " belligerent" status to the Confederate Navy meaning they could use their docks for 72 hours.
A major change in British policy came about during the "Laird Ram Affair" when U.S. diplomatic pressure forced the U.K. not to allow the sale of the Laird Rams to the Confederacy.
Intrestingly enough the U.K. did allow Union Army recruiting on British soil.
Leftyhunter