This question is pretty vague, and presupposes that England DID in fact assist the Confederacy during the ACW. I'd follow up by asking for clarification: in what way does OP presume that England did "assist the Confederacy" during the conflict?

To my mind, there are only a few instances or examples one could put forward to make the case that England assisted the Confederacy, and each of these was in a roundabout, indirect manner. For example, the Trent Affair did see England make an official protest against the U.S. government for boarding a British vessel (so as to intercept two Confederate diplomats). This was early in the war, and England seemed to still be feeling the situation out (and keeping all its options on the table). While they did make it clear that they wouldn't stand for the U.S. government stopping or detaining any vessels or subjects in the course of prosecuting the war, England never officially received any Confederate diplomats at court, and certainly never recognized the Confederacy as a sovereign nation. This incident was more about England setting the tone for how they wanted to interact with the U.S. government during the war (they were essentially saying they weren't gonna get pushed around).

Now, in a more direct way, England definitely helped out the Confederate navy by turning a blind eye to people selling them old ships, and allowing Confederate vessels to dock and outfit in their waters (this was a big complaint of Lincoln's administration), yet the British government never made any of this official. It's more like they just looked the other way when it happened. To illustrate their reluctance on this point, the British government did protest Confederate recruiting efforts in their territories (so, they didn't much like it when Confederates tried to recruit British subjects to serve on their warships).

Lastly, there was a market in England for Confederate cotton that had been smuggled out through the blockade, but again, this was never an official policy by the British. In other words, they never established formal trade relations with the Confederate government to make this exchange official.

So while England definitely had some relations with the Confederate government, they never formalized the arrangement, nor did they do anything that would potentially put them in direct conflict with the U.S. government (the Trent Affair being about as close to that as it came).

[Sources: James McPherson, 'Battle Cry of Freedom'; Tom Chaffin, 'Sea of Grey']