S01E15 (5th March 1970). Written by Elwyn Jones, directed by Michael Simpson

A group of confidence tricksters are preying on the elderly. John Watt dearly wants to catch them, but that seems unlikely – until a golden opportunity falls into their laps …

Two future Rentaghost alumni (Anthony Jackson, Jeffrey Segal) are members of the gang, along with Harry Landis. Parrish (Segal) is the smooth-talking front man – complete with clipboard he’s a very convincing gas board official. Knocker (Landis) is the sneak thief who rifles through the unfortunate victim’s belongings while Parrish keeps them talking with Corry (Jackson) remaining outside in the car, always ready to make a quick getaway at the first sign of any trouble.

There’s something more than a little disturbing at the thought of the vulnerable being tricked in this way. Several elderly extras are used to illustrate just how prolific the gang are, with the story concentrating on two victims – Miss Dobson (Joan Cooper) and Mr Partland (Andreas Malandrinos).

Joan Cooper (the wife of Arthur Lowe) was only 47 at the time of recording. So either she’d had a very hard life or some skillful old-age make up was applied. In material terms, the amount stolen from Miss Dobson isn’t too great but it’s the sentimental value (her mother’s rings, an Ormolu clock that belonged to her father) that makes the crime so hurtful. Cooper only had a handful of film and television credits to her name, which – based on the evidence of her cameo here – is a little surprising as she gives a powerful performance during her key scene.

Watt – present when Miss Dobson dissolves into tears – is incapable of offering any comfort (he leaves that job to Donald) but it’s obvious how much he wants the thieves caught. At first, Barlow seems less interested, but gradually he’s drawn in (and it’s his actions which ensure the episode ends with a nasty sting in the tale).

Although Cooper was acting elderly, Andreas Malandrinos was the real thing (he was 81). Mr Partland is certainly very doddery, although before I knew Malandrinos’ age I was almost convinced he was putting it on (perhaps he wasn’t quite as infirm as Mr Partland though).

Mr Partland is the owner of a great deal of silver, and the crooks plan to return and pinch the lot. When he tells his story to Barlow and Watt, Barlow’s eyes light up – if they allow Parrish and Knocker to carry out the robbery then they can follow them and catch the big fish. Watt’s understandably hesitant to put the old man through such an ordeal but Barlow ruthlessly overrules him (and easily manages to convince the vague and pliant Mr Partland).

Everything seems to go off fine, but the Task Force are only able to round up the minnows after all – plus Mr Partland suffers an attack after Parrish and Knocker leave. The episode therefore closes on Barlow’s unreadable face as he stoops down towards the prone and barely conscious figure of Mr Partland. We never know if he recovers or not – and it’s up to the viewer to decide whether Barlow feels any remorse …

Due to the subject matter, this is a grim story with only intermittent relief. One bright spot occurs when Donald meets Watt in the post office. He tells her not to call him ‘sir’ whilst she’s working undercover – and she takes this advice to heart by kissing him on the cheek and holding out her cheek for a reciprocal kiss! Later, posing as a mother with a pram, she attempts to use the perambulator as a weapon in order to stop one of the fleeing crooks (it runs an impressive way down a hill before crashing to a halt).