After some unpromising beginnings as a naval reservist, London clubman, and jazz band leader, Knight’s first undercover job in 1923 was to penetrate the extreme right “British Fascisti” movement. The BF was a far cry from the jackboots of Hitler or Mussolini. Its founder was a lesbian former ambulance driver named Rotha Lintorn-Orman. Its membership included the captain of the England cricket team and the Irish fitness fanatic William Joyce, who would resurface later in Knight’s career as “Lord Haw-Haw”.
https://www.theguardian.com/books/2017/apr/30/m-maxwell-knight-mi5s-greatest-spy-master-henry-hemming-biography-review-robert-mccrum