Long winded title, but this has been on my mind for a while. From somewhere around the post-WW2 period on, when the British nation was bankrupted and the empire setting, Right wing movements seemed to find a good deal of support. Enoch Powell gained support for his "Rivers of Blood" speech and anti-immigrant sentiment was high during the 60's. During the 1980's, when the Thatcher government was elected, many outlets of media presented a future evolution out of this into a dystopian British society. If I'm correct (and as a Yankee I might not be), I believe anti-immigrant and anti-Muslim sentiments are still problematic in Britain.
On the site, we've also recently seen an Enoch Powell timeline or two.
The question overall is how close was Britain, during that 1950's to maybe circa 1980's period of going Radical Right, and how much of a possibility was that.