It's not just that they're a bunch of insidious, racist scum. The BNP's policies run contrary to just every aspect of good governance in the modern world, and would ruin Britain.
Firstly, various employment sectors rely on immigrants. High technology industries rely heavily on getting the best talent, from abroad if necessary. Block that talent, you lose all the industry. Secondly, immigrants and people from immigrant backgrounds massively underpin certain sectors, like Britain's healthcare: say goodbye to them, say goodbye to about 20-30% of the UK's doctors and nurses. That means inability to cope with the sick. Many other sectors of industry would be similarly devastated. Higher education will collapse, leaving Britons unable to get good quality education. "British jobs for British people" is pretty useless when you've killed or driven out so many companies that supply jobs. And you say they'll ban welfare? Imagine the civil disorder with mass unemployment and no welfare. The BNP plans conscription. That means chucking millions of people into various government services, the government then has to pay them and their equipment for whatever service, whilst they don't do a job that brings money into the country. That's another recipe for bankruptcy.
I'd hope even racists who wants immigrants out would notice that BNP's policies will turn the UK into an impoverished, enfeebled, stagnant backwater of the developed world. Guess the BNP wouldn't have to worry about immigration anymore - no-one including the British themselves would want to live in Britain any more.
