It’s 1945 in New Mexico, and a test is about to take place: the Trinity testing of the first atomic bomb. A year on, a shady figure in a dimly lit library steals a file, a fledgling MI5 is investigating a Soviet spy ring, and Foyle, returning to the UK after his American troubles (and to ITV after a three-year hiatus), is plunged into the Cold War.
Cue a jolly two-hour tale that could be part Tintin, part Agatha Christie, but is wholly writer Anthony Horowitz on top form. It’s all done with consummate skill and elan, from the plausible characterisations and mysterious meetings in dark alleyways, to elliptical exchanges and beautiful period detail.
There’s also a real pleasure in reacquainting ourselves with a dependable and likeable cast of old favourites that includes Foyles’ driver Sam Stewart – surely being played with more than a gleeful nod to the jolly holly sticks tones of Joyce Grenfall by Honeysuckle Weeks – and of course the wonderfully lugubrious Michael Kitchen as the eponymous Foyle. Huge fun, right down to the radiation-suited strangers and red herrings.