Icingonthecake, I have tried, really tried to take on board posts on this thread that express similar sentiments to yours. Unfortunately, I have failed in my bid to be tolerant. My failing, perhaps? I just find the ignorance, and as HB pointed out, the lack of self awareness, let aloneshame depressing.
The guy you mentioned may not have been your friend, but you clearly bought into his ridiculous Daily Mail 'We aren't safe in our own country!' bullshit. (You said: 'He said the city is a dangerous place for a white man to live nowadays. That to me is awful. ')
I have lived in London all my life, from Camden to Camberwell, Harlesden to Hackney, and I think that that is the most ridiculous, stupid, hateful thing to say. I am not denying that racial tension exists in certain areas of London (obviously it does) but this 'Its spot the white man / we ain't safe among all these coloureds / foreigners!' attitude is despicable. Listen to it! Read it back in black and white. Rewind 60 years and replace the word 'coloured' with 'Jew'. Can you not see????
I would also like to point out, for maybe the 3rd or 4th time on this thread, that being black is NOT the same thing as being foreign (not that that should excuse prejudice against people from other countries, ie. genuine 'foreigners'). My DH was born in London. He was raised in London. He has a British passport. He supports the England football team. He pays a hell of a lot in taxes. hell, he even represents his country abroad in his work for the British Council. Our son will be similar. They are both black and have every right to live in London. If the likes of the bloke you mentioned don't like it, it really is there problem - hence why I am glad he left.
People have genuine fears and concerns about immigration, employment, housing. But stirring up hatred towards other groups of people won't solve those problems.