Immigration often becomes an issue during a financial downturn.
There are a lot of immigrants in London but many of them go unnoticed because they are pale skinned and very, very rich.
There are also a large number of immigrants to Spain who are pale skinned and disproportionately rich, obsessed with avoiding the local cuisine and only hop back to the UK to vote Tory once every four years or so.
Heck there a silly goon who doesn't pay a penny in tax here, was knighted by the British Monarch and is an active campaigner for Scottish independence and lives in the Bahamas.