I am not sure about Britain, but my impression is that in Germany, nobody is going to ban right-wing stuff (except the really racist genuine Nazi stuff -- but even here, the hurdle is very high. After all, we still have the neo-Nazi party NPD). For example, I have not ever heard the suggestion that Thilo Sarrazin's views should be "banned".
The problem I see when it comes to the memes of far-right people such as Sarrazin supporters is that they don't understand what "freedom of speech" is. When they say absurd things, or things worthy of criticism, they have to live with it that they're being criticized. But they hysterically mistake opposition to their views as alleged "ban" on their views. They can't live with it that people disagree with them. I assume that's projection -- if they were in power, they'd ban views that differ from their's.
What memes do I mean? Common in the German debate from the right side: "There is censorship in the media by a political correctness police". But as I see it, what they perceive as a conspiracy is just the consensus by the majority of people from left to moderate right, who have a basic sense of decency and respect for other people and minorities, that disrespectful statements, prejudices, hatred and xenophobic stereotyping should be avoided. The righties just don't understand that, because they don't have the slightest bit of respect for minorities themselves, had a bad education and thus don't know how to treat other people with respect. Of course it must appear like a conspiracy for them, when then 80% of the people or so frown when they advance their hatred and generalizations.
Another righty meme in Germany: "It must be allowed to say such a thing", suggesting it's not allowed to say the things they say. Ironically, they have been saying the very same things for decades now, and nobody has ever kept them from doing that. Every seven or eight years, there is another debate sparked by provoking xenophobic righties, and always, they said "we are breaking a taboo", although such a taboo never existed. Oh how short the memory of some is.
Especially ironic is that the moderate people in our debate are already discussing the problems that come with multiculturalism, integration problems of immigrants and radical opinions among Muslim immigrants. But they usually do that with a minumum of respect, avoiding stereotyping. The islamophobic righties ignore that, so they can claim they are doing something fundamentally new when they point to these problems. That's probably because this brand of righties (i.e. the Thilo Sarrazin crowd) have much less interest in actual debate and facts, and base their entire political worldview on primitive and lurid tabloids à la "BILD newspaper", than on serious media sources. Also, for them anything short of blind hatred of foreigners and immigrants, sometimes even outright racism, is "appeasement". And they never make any contributions or propositions when it comes to solving the existing problems -- their rants are usually limited to venting out hatred against aliens.
This kind of populist far right is really pathetic. And I think they are a much bigger threat to our political discourse and freedom, than any problems related to immigration will ever be.
Just my two cents.