Surely one of the enduring beauties of British culture has always been it's ability to suck-in and assimilate influences from throughout our ever shrinking world.
Our language and culture are constantly evolving e.g. the young people 'round my way have melded elements of West Indian patois and Indian languages into their Yorkshire dialect in the same way our grandparents and great grandparents assimilated Irish linguistic influences.
I guess what some people see as a 'watering down' of our culture is seen by others, including myself, as an enrichment. - not inter but outernational.