Great Britain’s opinion of the Civil War fluctuated along with the course of the war, starting off somewhat pro-Confederate in 1861 before slowly turning pro-Union by 1863 after the Battle of Antietam and the issuing of the Emancipation Proclamation. While I can’t speak specifically to the average Brit’s view of the war, I can offer insight from the British government and newspapers on to what the overall public stance was.

At the start of the war, Britain was pro-Confederate, though adverse to outright recognizing the Confederacy as a separate nation or aligning with them militarily or financially. Much of this was due to the fact that British textile mills relied on Southern cotton, and the Union blockade of the Confederacy cut them off from it. Textile mills shut down due to the cotton shortage, workers were left unemployed, and voices in the government and in the press (most notably the very pro-South Times) argued that supporting the Confederacy would rescue the textile industry. It’s worth noting that Britain was able to get cotton elsewhere (such as India), so while the loss of Southern cotton was felt it wasn’t single-handedly damaging the British economy. Pro-Confederate newspapers also portrayed Southerners as a genteel people who simply desired their liberty, and conveniently ignored slavery (which will factor into their eventual decision to withhold recognition or support.)

At the start of the war, the Confederacy was also the more successful, militarily, of the two sides. The British Prime Minister, Lord Palmerston, never gave his support publicly or privately to the Confederacy, believing that a decisive battle victory on the part of them or the Union would determine his stance. The government waffled about recognizing the Confederacy as their battle success ebbed and flowed. By mid-1862, more Confederate victories (albeit minor ones in the grand scheme of war) led to voices in government and the press to argue that mediating a peace with full recognition of Confederate independence was preferable to end the war (and access that Southern cotton again.) Both the Times and the Morning Post (the latter with ties to the Palmerston government) argued this. The Times even referred to the Union as a “mongrel race of plunderers and oppressors”; this was pretty typical of their view of Northerners during this stage of the war.

In the government, a motion was introduced to mediate a peace and recognize the Confederacy, and politicians like future Prime Minister William Gladstone believed that the Union would never be able to regain the lost territory again and supported the motion. Palmerston again backed off. This was all pre-Antietam.

In the essay I’m mainly drawing this from, James M. McPherson argues that Antietam (and also the Emancipation Proclamation) definitively ended mainstream British support for the Confederacy. To the British public and to most government figures, the defeat at Antietam was so crushing that they believed the war was effectively over. It wasn’t just the enormous loss of life, either; the recent Confederate battle successes had convinced foreign onlookers that they were unbeatable, and they were shocked that such an army, seemingly riding high off previous successes and against a near-failure of an opponent, could lose so badly. In short, it made the Confederacy look really bad. Palmerston basically dropped all notions of interfering in the war on behalf of the Confederacy at this point, which meant that without any government support on the table public opinion dropped off too.

Last but not least, opinions on slavery were much more negative than in the United States, north or south. Slavery had been abolished in 1833 throughout the British Empire, so by 1861 a whole generation of Brits had lived without slavery, and public opinion was (obviously) negative. So why, then, was opinion on the Confederacy mixed to faintly positive in 1861/early 1862? In general, the press chose to focus on the importance of cotton to British textile mills and the lack of success for the Union as reasons the Confederacy deserved to succeed, not on slavery. Potentially sympathetic views on the Union were also stifled by the fact that at this stage in the war, they did not emphasize abolition of slavery in their reasons for pursuing the war. After Antietam, Lincoln, emboldened by the victory and seizing the moment, issued the Emancipation Proclamation. Once the Union claimed the abolition of slavery as a goal for the war, it became impolitic to support the Confederacy, or else you were implicitly supporting slavery as well. Mass pro-Union meetings were even held across Britain in the wake of the Proclamation going into effect in January 1863. Richard Cobden, a member of Parliament, wrote, “Recognition of the South, by England, whilst it bases itself on Negro slavery, is an impossibility.” Most people concurred.

To sum up, the British public started off somewhat pro-Confederate, buoyed up by military successes, a reliance on Southern cotton for their textile industry, and a lack of commitment to abolition by the Union. As their fortunes waned, British opinion began souring, finally reaching the point of no return by Antietam, when any Confederate victory seemed lost for good. The issuing of the Emancipation Proclamation also generated support for the Union, and placed the Confederacy in a negative light by presenting them as dedicated to preserving slavery rather than just their independence (which...they were.)

My main source is “The Saratoga That Wasn’t: The Impact of Antietam Abroad” in The Mighty Scourge: Perspectives on the Civil War, by James M. McPherson, and all quotes are taken from this essay.