Integration is key. There are established ghettos in just about every country where an immigrant population exists. It is the human condition to seek out like folk, same colour, same language, etc.
In this moderate country of ours we tolerate these ghettos, think chinatown, Kilburn, etc, as long as "they keep themselves to themselves". Problems arise when some among them decide that our society needs to be changed. Some among them despise our values as being too moderate, too liberal and in need of change.
We allowed, because we uphold the principles of free speech, for some to actively and loudly criticise our values and our establishment, whilst ironically, in some cases claim all that our tolerant society bestows upon those less able to look after themselves, think Abu Hamza here.
We, everyone in this country no matter who, must begin to be a little less tolerant of those who wish to change by whatever means, our values and ways. We must not be afraid to speak openly to criticise the communities who shelter those that speak evil, no matter who they are.
Criminals are criminals.