If they won’t assimilate..
If people come to your country, they have a choice. They either assimilate into the prevailing culture, accept the cultural and legal parameters, or they separate from it. I’m afraid far too many of those migrants coming here over the past 30 years have chosen the latter approach and worse of all it has been indulged. That only encourages the creation of de facto ethnic ghettos. And all kinds of things then flourish within such societal Petri dishes as the grooming gangs scandal exposes all too vividly.