It doesn't seem to me reasonable to believe that the British people and the British government did not support the Confederacy.   The topic is far too complex to assert that. I would certainly be willing to see any evidence--before Gettysburg--that the government did not support the Confederacy--at least by extreme unwillingness to act against the building of the ships the Southern agent, James Bulloch, had in mind.

It certainly did seem--at least until the possibility of the South taking Washington seemed gone, that is, until Gettysburg--to the US MInister to Britain, Charles Francis Adams, that the British government was doing all it could to support the South without doing so overtly. His frustration is palpable.

"After almost two years in London, Adams was still ill at ease with the English. For all their politeness,    he could sense the almost universal antipathy toward his country, whether in the casual chat at ruling-class dinner tables or the carping tone of the editorials of the national press, or, most galling of all, in the honeyed insolence of the government leaders with whom he dealt." (deKay p 144)

"At his most recent meeting with Russell" (this is spring 1863) ," shortly after the debut of the "Florida", Adams came close to charging the British government with outright criminality for its disregard of his warnings about the two Confederate cruisers" (deKay p 145).

"Well-born Englishmen professed to dislike Yankees as much for their manners as for their dangerous democratic example to the lower orders. Many of the gentry expressed delight at the 'immortal smash' of 1861 which demonstrated 'the failure of republican institutions in time of pressure'. The Earl of Shrewsbury looked upon 'the trial of Democracy and its failure' with pleasure. 'The dissolution of the Union (means) that men now before us will live to see an aristocracy established in America'   Similar statements found their way into prominent newspapers, including the London 'Morning Post' and the magisterial 'Times', both with close ties to the Palmerston government. The 'Times' considered the destruction of 'the American Colossus' good 'riddance of a nightmare...Excepting a few gentlemen of republicans tendencies, we all expect, we nearly all wish, success to the Confederate cause'. If by some remote and hateful chance the North did manage to win, said the 'Morning Post', 'who can doubt that Democracy will be more arrogant, more aggressive, more levelling, and vulgarizing, if that be possible, than ever before'". (McPherson, p 551),

The newspaper quotes are from an entire book on the question:   Britain and the Civil War, by a historian named Adams who died in 1930.    But his book, it appears is back in print--on Amazon, no less. I may well do something I hardly ever do, and pay full price--the topic is amazingly rich and complex. Also, you can download the book through the Gutenberg project--though I sure can't imagine downloading a 646-page book.