If Geert Wilders had been allowed to enter the UK and show this film of his, hardly anyone would have battered an eyelid. Instead by denying him entry, the government has given him huge levels of publicity, turned him into a martyr for extremists and sent many people to watch his filth.
Here in the UK we seem to take a similar attitude to the British National Party and others. Time and time again we just give them publicity, reinforce their claim to be "the party with the answers the political establishment doesn't want You to hear" and make them ever more attractive to the politically alienated. As I blogged before in Time to end No Platform?, I think these methods are no longer working and can, if anything, be counter productive.
Instead let's provide constructive alternatives, stop providing favourable publicity and allow the extremism to wither and die. Freedom of speech is the freedom to say what you like. It does not mean anyone has to listen to you.