As for failure to integrate it's abundantly clear when Africans with London accents behead Britons
There's even a bit of East London called Gaza Strip
A good point that shows that we shouldn't have a problem with Islamic immigration - I assume you're talking about the murder of Lee Rigby in 2013, which was committed by two men who were raised as Christians and converted to radical Islam when they were adults. Or are you saying that we shouldn't allow black people into the country?
I'm not convinced that terrorism from muslims is all that common in the UK, despite us having a lot of people from Muslim countries, especially Pakistan. Terrorism is one of the things that usually makes the front pages and racist groups make a huge fuss over high-profile crimes committed by certain minorities. That's why you see lots of noise online about the Rochdale case but much less about other news stories involving white paedophiles such as
this recent one.
The
latest terrorist news from the UK is that a ginger-haired guy who felt discriminated against for his hair colour was arrested for planning to assassinate Prince Charles so that the ginger-haired Prince Harry would become king (AFAIK Harry is 4th in line, but I guess it isn't surprising that a crazy's plans don't make sense).
You can find examples of horrific crimes committed by pretty much any sizable group of people, and crime tends to be higher among poor people so it's easy to smear disadvantaged minorities, who tend to be poorer, as being violent or criminal.
My personal experience is that I've met dozens of people of African or Asian descent who were born in the UK, have mixed groups of friends, respect other religions, and are thoroughly British and utterly non-violent. That includes muslims, including some very devout ones.
In fact, I've only met one muslim who was prejudiced, and he was quite well integrated - a non-violent, clearly British man who wasn't even very religious, just anti-semitic. I've had far more experience of racism and violence from white, British people who didn't seem to be muslims.
Just because two people converted as adults to a rare extremist form of Islam and committed a murder two years ago only shows that there's a tiny proportion of psychotic nutjobs out there. There are violent extremists of all kinds, including plenty of right-wing, white, anti-islamic ones.
But, I could be wrong. Maybe Islam does make people violent, but I'm not going to casually take people's word for it without serious evidence. Are there statistics from a reputable neutral source such as university researchers, using recent UK data, correcting for social factors like poverty, that shows that muslims are more likely to be violent or criminal? If so, then do provide a link as I'd be interested to read that.