The Emancipation Proclamation was actually received negatively in the UK, contrary to popular belief; it was recognized as a pretty obvious attempt to tap into Anti-Slavery sentiments to stave off intervention at best, or an effort to incite servile rebellion in the South at worst, which is something the British really wanted to avoid occurring. The fact the Roebuck Motion was around into the Summer of 1863, until Gettysburg dashed it, is a good example of this.
As far as effects, it'll be decades before serious cultivation efforts at Egyptian and Indian cotton are made. They're too low quality and require additional shipping to compete with Southern Cotton. Britain will have also achieved the strategic objective of reducing the threat posed by the United States, as it's now surrounded on almost all or indeed all (depending on Mexico) of its borders by Pro-British elements. More importantly, the Mississippi River now lies essentially in British hands via the Confederacy, meaning that in a future conflict the possibility exists for London to divide the Union into two, doing grievous harm to any war efforts.