Sabotage! Espionage! Military! Chemistry! This is more like it. Despite an unfeasibly elaborate method for passing secrets, via a dartboard and a member of the subspecies canine lupus, this is an enjoyable investigation into traitorous goings on at an experimental satellite tracking station in rural Wales. Steed gets to pass himself off as a military psychiatrist(!) while Cathy is a chemist, in between lots of socialising in the club and the local bar.

After the extensive but ineffectual use of filmed footage in The Sell-Out, some judicious exterior shots enhance the atmosphere and sense of location in this one.

The sense of location is not, however, aided by the ‘Welsh’ accents. The cast appear to originate from everywhere on the British Isles except Wales, as do the accents. Painful at times.

Once revealed, the desperation of the traitor is very effectively conveyed but the increasing unruliness of his hair.

Steed is particularly ruthless in the standoff that resolves this one, to Cathy’s very visible distress; but he is successful. The lesson here is clearly that treating traitors and terrorists as sub-human is effective (and, therefore, presumably justifiable). It’s a very tense and well executed climax.