As I recall, the series was on Masterpiece theater in the early 80's, staring Michael Elphick and Ian Richardson. It was high comedy, and was essentially about a Nazi plan to destroy the British by infusing counterfeit British pounds into the British economy.
The mastermind behind the plot I believe, was Richardson, who plays a perpetually pompous but completely inept German officer who is Commandant of a prison camp. He needs an expert forger to carry out his scheme, and he finds Private Schulz, who is in prison for forgery. Schulz is given a free hand to forge the notes, but has a plan of his own, that is, to steal the counterefeit money right under the nose of the unsuspecting Richardson.
Schulz, unlike his boss, is street savvy and bright, but Richardson manages to inadvertantly foil every one of Schulz's schemes, much to Schulz's dismay and disbelief that someone so stupid could get the better of him.
Of course, Richardson never realizes what Schulz is up to, affording Schulz one opportunity after another to try to abscond with the money. Richardson trusts him completely, and in one of the later episodes, Richardson even sends him with the money, to England, to distribute and create havoc. Thoroughly enjoyable, with a surprise ending!