Dick Barton (Don Stannard) is an expert detective and man of action who, along with his companions Snowey (George Ford) and Jock (Jack Shaw) is travelling to the small coastal village of Echo Bay, ostensibly on holiday. However, there are foul deeds afoot in the sleepy fishing town, even though all seems normal on the surface as Dr Casper (Geoffrey Wincott) walks through the streets, greeting everyone he meets with a cheery hello. Dr Casper claims to be a Swedish biologist investigating the Colorado beetle, but when his new assistant arrives, their conversation doesn't cover insectology, but rather how to keep their true identities secret and how to get rid of Dick Barton once and for all...
Dick Barton Special Agent was scripted by its director Alfred J. Goulding and Alan Stranks, and was based on the hugely popular B.B.C. radio series of the day which related tales of derring-do and spy smashing to the homes of millions of listeners sat around their sets in rapt attention. However, when the early Hammer studios came to film the detective's adventures, the result must have looked laughable and ramshackle even then, so just imagine how it looks today. It mixes (presumably intentional) laughs with fisticuffs to create an almost surreal atmosphere, the equivalent of watching an amateur dramatics group's interpretation of the then-famed characters.
While Barton and his friends spend the first ten minutes of the film cheerily driving to Echo Bay, the mood only darkened by Jock's back seat bagpipe playing, the baddies are plotting to get rid of him. Two of Casper's henchmen are dispatched to hide in the bushes so one, who claims in a bizarre rendering of an American accent that, "I never miss", can adopt the sniper's position and take a potshot at Barton. It looks like the story is over before it begins as our hero slumps over the wheel and runs the car off the road, and the would-be assassins return to their masters to tell them the good news that their worries are over.
Not so fast, though, as Barton was only pretending to be shot (deliberately running the car off the road was entirely non-life-threatening, of course) and makes it to the village to meet up with his assistant Jean (Gillian Maude) and her housekeeper. While briskly paced, there's not much of a sense of urgency about the narrative as Snowey and Jock head off to the nearest pub, which is run by the villains funnily enough, and hijinks ensue with a pub trick (where Jock is promised four double gins!). In fact, neither the goodies or their adversaries come across as particularly threatening to each other for the first half: see Dick, Snowey and Jock's attempt to investigate the lobster pots which ends up with them capsizing their boat and having to swim for shore.
They are interested in the lobster pots because they found stolen jewels in their breakfast lobsters which had been delivered by the local fish mongers, who are also in the pay of Dr Casper. It looks like a straightforward smuggling operation, but Dr Casper turns out to be a Nazi spy left over from the war (fresh in the audience's minds at the time) and planning to give everyone in Britain cholera by poisoning the water supplies. Can Dick and his ever-growing network of allies foil him, and avoid getting kidnapped? Well they can certainly try! Full of lines like, "Reach for the stars, Barton! What a pleasant surprise - but not for you!", being countered by "You filthy swine!", the film is winningly ridiculous, impossible to take seriously and a must for bad movie fans. Music by John Bath (and the famous Dick Barton theme tune is present and correct).