This is somewhat counter-intuitive -- often one reads of Jews being seen as competition or resented for their role as money lenders even though in fact the latter is also counter-intuitive since being able to borrow money is critical for many businesses.
So was there something unique in the role of Jews in England or was it simply, by the 19th century, seen as old fashioned to discriminate against Jews by many, including merchants who had dealings with the Jews?
EDIT: This is mentioned in the Wikipedia article Emancipation of the Jews
EDIT: Perhaps this merits another question entirely, but as I responded to a comment below, I wonder if there are other instances of groups supporting Jews, even in countries where they ended up being expelled? I know of Bishops and Popes who did try to speak against anti-Jewish factions but nowhere other than this instance in pre-20th century Europe do I hear of support. Interestingly, abolitionists (in at least one notable case) in the USA were sometimes openly anti-Jewish. (Wm. Llyod Garrison mentioned J. P. Benjamin's religion in a very negative way.) I am of course aware of the Turkish Sultan who was, out of enlightened self-interest, very helpful to the Jews after the 1492 expulsion from Spain.