Which event significantly influenced British public opinion against the Confederacy during the Civil War?

The Trent Affair significantly influenced British public opinion against the Confederacy during the Civil War because it highlighted issues of maritime rights and international law. This incident occurred in late 1861 when the Union Navy intercepted a British ship, the RMS Trent, which was carrying two Confederate diplomats to Europe. The Union's aggressive action was seen as a violation of British neutrality and sparked outrage in Britain, as many viewed the act as a disrespectful affront to British sovereignty.

The British government, which was already sympathetic to the Confederacy due to economic interests in cotton, found itself in a delicate position. The public reaction in Britain was largely negative toward the Union’s actions, and it increased calls for the British government to support the Confederacy. The incident ultimately put pressure on the United States to release the diplomats to avoid escalating tensions that could lead to war with Britain. Thus, the Trent Affair galvanized anti-Confederate sentiment in Britain, revealing how actions taken during the war had broad international implications that affected perceptions of the Confederacy.