Undermind

Undermind was a very unusual British science fiction thriller series for its time in that there wasn't a rocket, flying saucer or extraterrestrial to appear at all over the course of its run.

Over its eleven episodes Undermind told a story about alien subversion where an alien force, that was never identified by name or location, sought to establish a foothold in Britain by undermining society and morale. These aliens had sent high frequency signals from space that are picked up by people who become brainwashed into subversive acts to create a climate of social unrest. 

The series villains ended up being everyday people who suddenly underwent a dramatic change in their personality, and behaving or acting in ways totally foreign to all those that knew them. But they all shared one small thing in common - an acute susceptibility to high frequency signals. 

Undermind was created by writer Robert Banks-Stewart and was produced by Michael Chapman. The series main cast consisted of two regular players - Jeremy Wilkin as Drew Herriot and Rosemary Nicols (who'd later go on to star in Department S) as Anne Herriot - while each episode featured new characters and guest stars suited to that weeks story. In the series premiere episode "Instance 1" (a.k.a. "Onset Of Fear") written by Robert Banks-Stewart, Drew Herriot returned from Australia to find his policeman brother Frank (Jeremy Kemp) had provoked a scandal involving a top politician. Appalled by this uncharacteristic behaviour, Drew and his brother's estranged wife Anne searched for the cause behind Frank's strange actions. With the help of a psychiatrist, they discovered that Frank had become 'emotionless' and uncover a web of similar cases - the victims all being susceptible to high frequency signals. Frank killed the psychiatrist, Dr. Poulson (Paul Maxwell) and tried to have Drew and Anne eliminated. But in the end, it was he who was shot, and as he died, he told Drew: "There are more of us..."