I am in the U.S. and she said it was the Muslims. They have taken over and made places unrecognizable.
It would very much depend on where she visted then. The Muslim population of the UK is only 2-3%. However, they ghettoise. So where in vast swathes of the country (such as where I live) there are very, very few Muslims to none at all, if your aquaintance has visited inner Birmingham there will have been very many immigrants. Part of the problem is that the UK has always had very few immigrants and now, in this global age, their numbers have increased. However, many are hard working and the non-white population of the UK is still only 8.5%