Plenty of furrins, like some of my ancestors, came to London in the 19th Century because of the trade links. Then the Huge Knots (probably another ancestor there) 150+ years before that seeking life & liberty free from savage persecution.
That said, 36% foreign born is quite high. Probably more than that by now, in fact, judging by how surprised I sometimes am to hear English being spoken. NTTAWWT!