[4][5][6] In 1917 he founded the Order of the Red Rose, an anti-Semitic group opposed to finance capitalism, with the zoologist George Percival Mudge, and the academic Arthur Gray.

[10] In his pamphlet An Introduction to the English Mistery, Sanderson wrote that there were two types of "aliens", namely "the Dutch, Danes and other peoples of north-west Europe" vs. "some races on the other hand differ very widely from us both in character and tradition".

[12] The fact that Sanderson was a very small man whose own illness left him confined to a wheelchair did not stop him from preaching the doctrine that only the lives of healthy, attractive, and well off people mattered as he had no compassion for the poor and/or the sick.

[12] Dan Stone has stated that the importance of the English Mistery lay "in the fact that it had links, both personal and ideological, with much wider strands of thought in interwar Britain.

[18] By 1933 it was said that Wallop had "attracted around him a band of devoted young men, known collectively as the English Mistery, who seek the ideal of aristocratic rule" in a "semi-masonic order".

John Platts-Mills belonged to the group;[20] he was recruited in 1931 via the Apollo University Lodge in Oxford and Godman Irvine, being driven to Lincoln's Inn to meet Sanderson.

[24][25] Others were Rolf Gardiner and Graham Seton Hutchison,[26] founder in 1933 of the pro-Nazi and anti-Semitic National Workers' Movement,[27] and the retired army officer Cecil de Sausmarez.

The officers of the Mistery were Thomas Scott-Ellis, 8th Baron Howard de Walden (High Steward), with William Sanderson, Roger Gresham Cooke, John Green and Henry Snell.

[32] The English Mistery envisioned their ideal England as a country with a strict hierarchy and inhabited by a nation of "racially pure" Englishmen who were led by an absolute monarch and supported by strong leaders.

[32] In the group's view, "submissive" races and peoples could be the victim of brutalities and slaughter, but to them this was a good thing: Surely, therefore, the time has come to recognise the inevitability of violence and sacrifice, and consciously to select the section or elements in the world or the nation that should be sacrificed.

[35] The British historian Daniel Stone noted that antifeminism was one of the strongest motivations for the Mistery as the group's publications, especially those by Anthony Ludovici brim with resentment and fury over women making demands for equality.