The final episode of the 'Tinker Tailor' incarnation of Special Branch. It would later be relaunched in an all film format as a crime show with an all new cast.
The main story is that Special Branch and Moxon think that Nato's best code breaker and chess grandmaster Christopher Haddon might be of interest to the Russians. He is due to take part in a major chess tournament where he might be pressured by people from the Eastern Bloc.
Inman knows how to play chess a bit and he urges Jordan to learn the game. When Haddon collapses during a chess match it seems an attempt has been made to have him hospitalised. Moxon wants him taken somewhere more secure. Inman wonders just how Haddon managed to get poisoned in the first place.
Jordan is startled to learn that Christine Morris has turned up again. This time she wants to come over to the British but Moxon regards her as an embarrassment especially has she doesn't have anything substantial to offer in exchange. Jordan is prepared to give up his career up to keep her safe.
I just could not buy why Jordan has this deep desire for Morris and make such a big sacrifice for her. He is also supposed to have that fancy upmarket girlfriend he lives with. Morris has been in and out of the series since the first episode and has showed herself to be untrustworthy.
There was no urgency between the Jordan and Morris here. If you are thinking of fleeing to the Irish Republic, maybe making love and then chatting is not a good idea.
At least it signed with Moxon being able to again outmanoeuvre the Russians.
For Derren Nesbitt, Special Branch was the highlight of his career. It was detoured by a a spousal abuse conviction.