Let's have a little commonsense here.

The BNP is a legitimate political party, with whose policies I largely disagree. Those who brand them Nazis miss the point that the real Nazis were in fact National Socialists. Still, as I've often said, politics is a circle: if you go far enough on one wing you'll meet the extreme of the other wing.
If the BNP do well (and, personally I hope they don't but UKIP do!), it is because the other mainstream parties have failed. Hearing mainstream politicians bleating on about the BNP is pretty appalling as they have driven many disaffected voters towards them, no matter how extreme their policies are to most people. We now live in an increasingly totalitarian society, where integration has meant the erosion of traditions and values, where political correctness is enforced by laws, where people are discouraged from showing any form of national pride (such as respecting our armed forces) and, finally, where 90% of our laws emanate from unelected bureaucrats in Brussels. Where is the referendum on the Lisbon Treaty?
No, any successes by the BNP will not reflect the successful sale of its policies, but the dismal -
truly dismal - failures of Labour in particular, but also Conservative and Lib Dem politicians, to understand the aspirations of the populace. For that they need to hang their heads in shame.
I do not support the BNP's policies in any way, but I support its right to exist as a political party. Any attempt to gag them is, of course, as odious as sections of their manifesto. Plus, of course, the more mainstream (and seemingly endemically untrustworthy) politicians rail against them, the more their support will grow.