The latest BNP membership list is apparently about to be published again.
This may, or may not be the one you can find at Wikileaks (a search for "wikileaks bnp membership" will find it).
It's depressing to see how many members they seem to have accumulated in my old town back in the UK.
On balance, I'm in favour of publication. Not just of the BNP, but of all parties (but not necessarily phone numbers or email addresses which appear in this version - too much easy opportunity to cause harrassment). If you are going to fund a political party, and try to manipulate the public into voting for it (which is essentially what you do by joining a party), then there should be full disclosure. That has to be supported by strong anti-discrimination legislation; no-one, not even a BNP member should be turned away from a shop, or with a few exceptions, from a job.
Footnote:
Since the last publication, the number of BNP memebrs in Canada seems to have grown quite significantly, mostly over in British Columbia and Alberta. Presumably all British expats.