It's nothing new.
The estate build where I live was started in the 1930's and expanded through the 1950's as London started to grow post war.
Most of the original residents here, came from areas like Brixton, which became settled by West Indians. I am talking about 1950's attitude here before anyone leaps on me. White people moved to get away from the ghettos that started to spring up and drive down their property prices.
It's a slow gradual process, but I'm seeing the same thing here again. that generation of 1950's immigrants have grown up, and need to buy property so they are moving out, and the white people here are on the move again - this time they are older with golden pensions and can afford to move right away to Devon and the like, rather than a few miles.
As ever, the whole thing comes back to education and social housing. I can only talk about relatively local places - so if the council decide to house eg all the Somalis in Thamesmead, another ghetto is created, ditto all the Romas in Crayford. IF they were a wide distribution pattern, ghettos wouldnt exist, people would be able to integrate more easily and thus become more easily accepted.
FWIW - I dont understand this whole Polish thing that seems to be going on. 200,000 Poles settled here after WWII - there was never any issues 80 years ago with them settling here. They were much loved and accepted into the community, they managed to establish their own churches and traditions without ostracising the local communities they moved and married into.
I think that is possibly a lot of the issues surrounding mass immigration, the ghettos. If you want to leave Somalia and settle here and become a beneficial member of British society - no problem; however if you want to some here bringing all the strife of a war torn country, with all its tribal issues and re create Mogadishu - big problem for those living in that area.
*I don't like 'ghetto' but I cant think of another adequate descriptor