18bBritain, 1942. We enter 18b as three women are being questioned on suspicion of endangering the state, under regulation 18b, a law that allows the imprisonment without trial of suspected Nazi sympathisers. The women have been in prison for six weeks, and now it’s up to Charles Lyon-Jones and William Thompson to interrogate them.

18b by Nottingham New Theatre puts a human face to the law in the form of detainees Violet Mortimer, mother, Nazi fraternizer with links to the British Union of Fascists (BUF); Millicent Bowe, nervous chatterbox and distributor of anti-war propaganda; and German-born Joanna Mauer, government secretary, interned, it seems, simply for having a BUF leaflet in her pocket.

18b deals with some substantial concepts, but rather frustratingly, makes meaningful use of none of them. There’s the potential for some real meat here: discussions of fascism, democracy, nationalism, pacifism and patriotism. There are passing references to subjects with contemporary relevance: a dissatisfaction with a coalition government, the broken promises of liberals, the reactionary hostility instilled in so many in the wake of terrorism. But it’s so brief that there’s no way any real symbolic connection can be made.

The dialogue itself is well written and the play is well executed; the accents are polished, the costumes are clean cut and the set looks authentic. The lighting is subtle and the crackly 1940s music is apt. The cast gives a solid performance and with better material, would be entirely captivating. All in all the production is neat. But everything lacks significance. It all feels like a missed opportunity.

18b’s roundabout script is finished off with an abrupt and inconclusive ending, just as you were getting ready for some real grit, which is a shame considering that everything but the plot was super slick. Visually and audibly a vintage dream, but ultimately superficial.

18b plays at ZOO on until 25 August 2014 as part of the Edinburgh Fringe. For more information and tickets, visit the EdFringe website.