A military coup and/or junta in the UK in the 1970s is not ASB. Walter Walker "taking the plunge", in 1972, being backed, and succeeding, that is ASB. You need a very different 1960s, or a huge PoD, like the IRA assassinating the queen.
I have had this idea of Heath winning in Feb 74 with a narrow majority (they won votes than Labour anyway), the Unions get more and more militant, Heath loses control and Walker could have lead a quasi Military gov to restore law and order.
From what I read out of this, it seems that Sir Walter was thinking more of a military-run government led by either a strongman general or by a junta... 'kind of what was going on in about every other South-American country at that time. From the quote, I do not see Sir Walter contemplating a Nazi ideology of racial purity and purging of all un-German (un-British) thinking. In fact I do not even see him endorsing Italian Fascist or even Spanish Franco-ist ideals.
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... I was saying the most likely Fuhrer would be Bowie. Which is, of course, to say that it is quite impossible there would have been any Fuhrer at all.
Er, Fascist Italy was a monarchy. Please be careful before making statements like that.