The same document presented a grid of 14 options for increasing compliance which included “use media to increase sense of personal threat”, a tactic which was seen as having a “high” effectiveness though spill-over effects “could be negative”.

Some Sage participants now admit to feeling “embarrassed” by such advice.

One regular Sage attendee said: “The British people have been subjected to an unevaluated psychological experiment without being told that is what’s happening.