But then, that's true of any person in any country.
Although I am apparently a fairly Anglo set of Anglo Saxon, like most UK nationals, I have ancestors from Ireland, Scotland, Wales and even Portsmouth. Plus, the Romans lived here for 400 years, and before them there were at least two distinct waves of Celts who seemed to have arrived from France and Belgium. No idea where they came from before that.
Then, in earlier times, the Phoenecians used to come to Brittain to get tin. More than a few of them left their genes in the pool (or perhaps they left their jeans in the pool, when they washed them?).
And...
So it goes on.