After Simon comes to the aid of a runaway horse ridden by Jeri Hanson (Mary Tamm), he finds himself embroiled in the murky world of espionage.  Jeri’s sister Christine (Diane Keen) was convicted of passing military secrets and is six years into a prison sentence.  But just one day before she’s due to be released on parole she escapes.

This was engineered by Sir Charles Medley (Geoffrey Keen) of the Ministry of Defence.  Jeri tells Simon she’s convinced her sister is innocent and it appears that Sir Charles arranged Christine’s prison-break in order to flush out a traitor in MI5.  But who can be trusted?  In the world of intelligence, things are not always as they appear to be …..

The Debt Collectors was written by George Markstein.  Given his background (script-editor/writer on series such as The Prisoner, Callan and Mr Palfrey of Westminster) it’s no surprise that he delivered a dense story set in the world of British Intelligence.

And after finding some of the previous episodes to be rather linear and straightforward, it’s a pleasure to have one where people’s motivations aren’t immediately obvious.  Things appear to open normally enough, with Simon coming to the rescue of an attractive young woman.  But she’s under surveillance and when Simon is later told not to speak to her again this only strengthens his interest.

By the time this aired, in December 1978, Mary Tamm was already more than half-way through her single season as Romana in Doctor Who.  Here, she seems to be the archetypal ROTS heroine – her function in the plot being little more than providing a decorative presence and also the excuse for the Saint to become involved in the story – but there’s a twist in the tale later.

Of more immediate interest is Diane Keen as Christine.  An actress who hardly seemed to be off the television screens in the 1970’s and early 1980’s, her first scene (behind prison bars) sees her playing a hard-bitten old lag.  This is rather a stretch for Keen and it’s no surprise that once she goes over the wall Christine becomes much more of a vulnerable character.

With the revelation that there could be a traitor in MI5, several possibilities present themselves.  There’s Sir Charles and also Simon’s MI5 contact Geoffrey Connaught (Anton Rodgers).  Geoffrey Keen, best known today for playing the Minster in the James Bond films, is perfect casting and Rodgers, later to carve a niche as a sit-com performer, shares some decent scenes with Ogilvy.

The story does have a few niggling plot-holes.  Why was Christine stuck in prison for six years before Sir Charles elected to use her to flush out the mole?  And since she was due to be released the following day why engineer a prison break?  If she’s on the run then presumably that makes her more of a target for the mole.  But since she doesn’t know his identity, Christine is ultimately something of a red-herring.

Whilst the looseness of the plot (which is a little surprising given Markstein’s background as a script-editor) is a slight irritation, there’s more than enough happening to negate these quibbles.  Apart from the already mentioned performers, the likes of Neil McCarthy (a familiar television face) and Bob Shearman (best-known for his regular role in The Sandbaggers) help to bolster an already impressive cast.

The Debt Collectors is a cut above the average ROTS script and rates four halos out of five.