We are not a secular state, religion is linked to the Sovereign (defender of the faith) and to government, however we are becoming more of a secular society there is no doubt about that and as such extreme views will be aired with all the freedom that allows. Islamic extremists are no different to Jewish extremists or christian extremists, if you have ever heard some of those christian fundamentalists in the U.S. speak then you would be very worried indeed and one of the biggest atrocities in the U.S was carried out by just such a person.
France is a secular society yet supports the Catholic Church and their buildings but it is written in to their constitution that any 'new' religions coming into the country must be self funded and that includes Islam and mosques, they get no grants or help what so ever in the building and maintenance of these buildings, yet France has the largest Islamic population in Europe, you would think, wouldn't you that they would all want to come here.