The threat they won’t face 

Mr Martin, the atrocities  of which you write were not Christian but in violation of Christianity. Christianity is fundamentally about the peaceful preaching of Christ, not armed violence.   Christianity had a great following and was seen as a vehicle to power. Institutions like churches made claim to its virtues as their own. They hijacked and abused its name. For centuries the Christian God has given political warmongers the “right” to overthrow their enemies and commit regime change in other sovereign countries. True Christianity is the essential pillar on which Western democratic civilisation is built. Islam on the other hand was born of the sword. It has grown out of violence and continues in the same vein. It is 700 years behind Christianity. Not only is it unable to assimilate with Western civilisation,  but aggressively attacks it,  declaring it the enemy. Across Europe  in London, Luton, Paris, Malmo and Stockholm and Dresden, Islamic mobs have formed no-go areas where even the police and emergency services are in fear of venturing. Blatantly publicly promulgated is, “No more democracy only Sharia law”. That is a political cult posing as a religion. By its very nature, Islam is diametrically opposed to democracy. 
I did not say “London is a majority-Muslim city”. My words were, “a Muslim-majority electorate”. Were it not so, Sadiq Khan would not have been elected as London’s mayor. Whether he ran on the Labour ticket or not is irrelevant. He is a Muslim who in the past has defended jihadists in courts of law. We must differentiate between the totalitarian ideology of Islam and Muslims who are human beings. 
It is quite obvious that the majority of Muslims who enjoy peaceful, assimilated lives in Western democracies have never read their holy books. Similarly, were the powers-that-be in Europe to familiarise themselves with true Islam, they would be forced to confront it as an enemy of all that they stand for. Western civilisation is dying because its guardians are spineless appeasers, avoiding a fight out of fear of jihadist reprisal.  
A peaceful Islam would go a long way towards creating  a peaceful globe.
JC Wilcox