Department S: The Bones of Byrom Blain

Like A Small War of Nerves, this is another Department S episode that - to me at least - feels very like a late Avengers episode, in plot, underlying themes, dialogue, & even bizarreness.
At first gasp, the name Marling Dale, the army base at which the events of the first scene of this episode happen, sounded extremely familiar. I was sure it was used as the name of a location in The Avengers, & am disappointed to discover that the research station in The Positive-Negative Man was called Risley Dale, but I'm still hoping to post in the future that Marling Dale is used elsewhere when I find it!
Jason King starts off the episode in his usual playboy mode, but soon moves into all-knowing Steed mode. When he searches Blain's car, it fees very much like scenes in How to Succeed...At Murder, & The Fear Merchants, where Steed examines a car, only with the chauffeur in this case taking the role of Mrs Peel.
If this were an episode of The Avengers it would be one of the ones where a member of the Establishment is corrupt. It even has the undercurrent of distrust of technology, in this case the doubtful results given out by the computer, named Auntie. The bizarre cover-up, of planting skeletons 'made to measure' (as Jason King puts it) in place of people kidnapped, covers a typically grandiose Avengers-style plot for world domination by infiltrating the world's intelligence systems. The hypnotism motif is another classic Avengers device.  The un-straightforward nature of the crime propels this story into a weirdness that even exceeds Department S's normal remit.
In fact, the Department don't feel so much like a police department as they could do, at all. It is episodes like this which showcase the reason for the oft-repeated idiom that Department S so wanted to be The Avengers. For myself I personally like the  episodes with an Avengers feel for themselves, they were one of the things that attracted me to this series in the first place. This is not to deride the jetset in sophisticated - for the time - locations episodes: I like them for different reasons, but I personally prefer these examples.
I love the scene of King dining at a 'pub' called The Nag's Head, which he obviously disdains right from the start. Certainly the sophistication of the menu, wine & waiter in evening dress would be way above any 'pub' of the time! - in fact would make it much more like a sophisticated inn like the Spread Eagle at Thame. But nonetheless, poor King for having to put himself through that trauma! The Nag's Head, however provides the forever England setting for much of the action: an alternation between the corridors of power and a village pub creates the required Avengersland feeling.
Sullivan takes on a Tara King role, by forcing his way in to see the general responsible for the project Blain was working on, creatively yet fruitlessly. When he learns the magic words 'Operation Groundshield' the general unbends to see him in an hour. Sir Curtis takes an a Mother role, picking up on the more vulnerable aspects of Mother's personality in being among those kidnapped, replaced by a skeleton, & hypnotised.
Actually, I think I may be overstating the Avengers borrowing: if you take away the Avengers features, you're actually left with a decent detective story. It's also one that manages to be puzzling enough to maintain its interest to the end, the real plot covered up by the skeletons is real enough to be convincing. The only completely unreal element of the story is actually the skeletons: it is inconceivable that in the time frames available a person could be reduced to a hinged & animated skeleton with connected bones and no flesh! That said, the incredible plot device fulfills its function of an effective diversion. Within the skeleton as distraction device, a further improbability is raised when the plotters at one point are seen to produce a skeleton for Annabelle: it would be incredibly difficult to get dental record, etc, necessary to create the skeletons, at short notice!
The story is also paced just right, the only fluff is where King says he's been dragged across Paris when he's actually come from the Caribbean, the supporting cast are just right for their parts & don't overpower the leads. All in all, this is an excellent Department S episode.