Michael Morpurgo, like all good tale-spinners from the time of Homer, knows that a story comes much more alive in its audience’s imagination if two-dimensional characters have their basic black or white outlines highlighted by flashes of grey. Friend or Foe has been adapted by Daniel Buckroyd for a new production which leads its young audience – not to mention their elders – very subtly into an adventure story that poses a whole panoply of moral dilemmas.

That young audience at the première performance was immediately gripped by the story of two boys evacuated to Devon from London at the height of the Blitz, learning the rhythms of the countryside and discovering that modern warfare reaches across remote moorland as well as orthodox battlegrounds. And it made up its own mind over Tucky (Mathew Hamper)’s and David (Paul Sandys)’ different attitudes to the discovery they make and how it can be reconciled to their own situations.

Both Hamper and Sandys are excellent as the boys. Their elders are more than just adult authority figures with Janet Greaves as the bossiest of teachers and the most cuddly of farmers’ wives. Michael Palmer gives two well-contrasted performers as Mr Reynolds, the farmer, and one of the crash-landed German airmen. Chris Porter plays the other roles.

It is a merit of Buckroyd’s staging {Matt Cullum]'s movement direction and the design work of Keith Baker with that of Tom Lishman (sound) and Mark Dymock (lighting) that the action flows seamlessly from the naturalistic to the impressionist with simple scenery and props and very well-judged  effects. Overall, it's a notable achievement.