This is a profound question that merits more than a simple slogan answer because what brings this question and the BNP to light is complex, misunderstood, and then used for political gain.
The first thing to realize is that the British soldiers who died fighting went and fought for their country. Why their country sent them is an entirely different matter and it certainly was not just to fight Fascism! The Bank of England and the Military Industrial Complex might have a little to do with it as well.
The reality is that those common folk who feel undercut by globalization and the pillaging of their wages by foreigners have every right to be upset. The problem ends up when their reasons for being upset are used by opportunists to get into power. There is no reason to prey on the fears of these people, as the BNP and the like right wing parties in the EU do, because their complaints are sound without it! All it does it diminish the ability to solve those very problems.
Obama, Brown, Sarkozy, Merkel and the likes are all part of the same club. They are globalists who adhere to the instructions of the Fed Reserve, the Bank of England, and the EU central bank first. Their interests lie with the multi-national corporations, banking interests, and military industrial complexes. Cheap labor, outsourcing, and trade deficits are of no consequence to them since they are under the rule of a monetary system that enables them to print money for programs and stay in power. Since the average Joe has no understanding of inflation or anything else really, the system continues to its natural conclusion:
A deflated currency, loss of sovereignty, and end of the nation state.
Parties like the BNP take people with perfectly good qualms about the system and ruin them by linking them with ridiculous and baseless nonsense, thus ruining the original qualms alongside.
The only irony is that if the British soliders really died fighing Fascism, it only lead to their children and grand children surrendering to a world Fascist state. That is where we are heading and people are too worried about racist rable rousers to see that those who really vote for them have actual reallly good claims to being upset.
The message is right but the packaging is all wrong. It is for that reason that the main parties always remain in power. The financial elites use the fringe elements mis-use of public sentiment to maintain control over the rest of the public. If Britons want to stop dying in wars they should worry about getting rid of the Bank of England before getting rid of the foreigners.