The cast of Duncton Wood at the Union Theatre
The cast of Duncton Wood at the Union Theatre

A musical about cats seemed far-fetched at the time but one about moles – presumably an underground production – may prove a beast too far. One mole in Wind in the Willows is quite enough to be going on with, thanks all the same.

But the idea to adapt William Horwood's 1980 cult best-selling novel (the first of a trilogy) must have struck composer Mark Carroll (the singing actor is currently appearing in Memphis) and librettist James Peries as promising material when they realised the book was like Lord of the Rings out of Watership Down.

And with support from Cameron Mackintosh, director Michael Strassen and designer Jean Gray have supplied a knock-out visual treatment with a cast of human moles variously decked out in furs, skins, leather straps and vicious claws, something burrowed, something new.

They assemble for the ceremony of the stone on Midsummer Night's Eve deep in the forest, evocatively illuminated with lanterns and moonlight by Tim Deiling. They sing for the right to pray, their religious identity. Their community is under threat from a vicious mole of nature and territorial savage, Mandrake (Anthony Cable), with sunken cheeks and a deep, angry voice.

Trouble is, too, that Mandrake's daughter Rebecca (Amelia-Rose Morgan) is in love with the heroic rebel Bracken (Josh Little), who sings loud and often about destiny and saving his loved ones, but not before one of the countryside copulatives molests Rebecca very unlike a mole; it's a full-on human ding dong in the glade. Bracken gets severely wounded but is restored to life by Rose the Healer (Anna Stolli), the resident holy moley.

This all goes on against a barrage of anthems, power ballads and chorales that are well structured – and very well sung – but somehow lacking that special "Les Mis" ingredient of, well, oomph and originality. There are no great tunes but some good harmonics and melodic phrases, and somehow a mournful ensemble of repressed and bereaved moles does not sound as ludicrous as it does in this sentence.

Strassen's talent for get-out-of-jail staging in this tiny space yields some complex and brilliantly conceived sequences, especially in that dole of a mole number where they all suddenly lift a raffia roof, or convene for another set of obsequies after the rain and renew their stone moans and boulder smoulder. Great small band, too, lurking in the undergrowth under the musical direction of Josh Sood.

Everyone in the show is very good, and very earnest, with Oli Reynolds and James Sinclair notable as two mole-ish cavemen, Nadia Eide (keeper of the stone) and Rosie Ladkin in the ensemble, and Trevor Jones as an old wise mole who is re-born as another one. As Hamlet says of his paternal ghost on the battlements: "Well said, old mole! Canst work i' the earth so fast? A worthy pioneer!"

Duncton Wood runs at the Union Theatre until 20 June. For more information and to book tickets, click here.