It has long been on my list of films I want to see, though I suspect part of its mystique lies in the fact that its director Michael Reeves died at the age of 25 shortly after making it.
The best summing up of the film came in the documentary about British horror films that preceded it when someone described it as a British Western. The score and the open spaces of Suffolk give this impression, but it has more to do with the film's vision of a society riven by civil war where strange beliefs can flourish. We radicals know that it happened in politics with the Diggers and Levellers, but it happened in religion too and the results could be less benign.
For the film does have some basis in historical fact. In an essay on Witchfinder General Quentin Turnour writes:
although neither Hopkins or Stearne were historically the sort of melodramatic “anti” Don Quixote and Sancho Panza sketched in the script, the film has a sense of responsibility to historical facts and logic rare in low-budget studio films.And if it is a Western, then it is a dark one. Its hero is played by Ian Ogilvy, who was clean cut enough to play the lead in The Saint in its brief 1970s revival. He is also a minor member of the British acting aristocracy in that his mother was John Mills' first wife.
But as Turnour says:
Ogilvy's Marshall begins as an anguished gentleman-officer, forebear to the earlier fine, politely upset warriors of David Lean and Carol Reed (and Dirk Bogarde's agonised trench-knight in Witchfinder General's near contemporary, Joseph Losey's King and Country, 1964). But by the end he has become the axe-welding avenger of every schlock-Horror quickie. Reeves' achievement is that this hollow moral resonance is the film's crucial affect.This reminds me of the insight from the philosopher Jacques Ellul that David Boyle is fond of quoting: when you fight someone you become like them.