We are in a small Cotswold market town in 1810. It's the height of the Napoleonic wars, fear of Bonapartist spies abounds. A stranger rolls into town - a roving man whose profession is rounding up wild horses for the military - and wins the hand of the daughter of the town Constable in a bare knuckle prize fight. Somehow, you just know that there's going to be trouble.

When Ralph Vaughan Williams wrote the score for Hugh the Drover, he was fresh from a spell of studying with Ravel, and it shows in the richly varied colours of his orchestration. It's not that it sounds like Ravel - the music is far too imbued with English folk melodies and rhythms for there to be any mistake about that - but the enormous number of different orchestral tricks is strongly reminiscent of him: as Vaughan Williams put it, Ravel "showed me how to orchestrate in points of colour rather than in lines". The result is palpable even given the constraints of an orchestral reduction for thirteen instruments in a small theatre: I haven't heard the original so I can't judge how much was missing, but it seems to me that Oliver-John Ruthven has done an impressive job of preserving vast quantities of orchestral colour with very small forces.

Ruthven was less impressive on the night, however, in that his Dionysus Ensemble were simply too loud for his solo singers, by a wide margin. If you like serious fortissimi, the balance was fine in the chorus: it was quite a large chorus and they they sang with huge verve, producing an awful lot of power, but most of the soloists were struggling to make themselves heard. It mainly showed in the diction: in the lyric numbers, I couldn't make out more than half the words - something I expect in a large opera house with surtitles, but not in a pub theatre.

Diction apart, there were some good performances. David de Winter acted the title role beautifully, with warmth and openness, although I would have preferred a more expansive voice to match the acting: he often sounded a little clipped and I wanted the phrases to flow more generously. He was outsung by Ed Ballard as the villainous John the Butcher, which is not the way it's supposed to go. As his beloved Mary, Elaine Tate was the reverse: the role was very nicely sung, but her facial expressions lacked variety and didn't always match the words. The show was comprehensively stolen, however, by Barnaby Beer as the Showman (and later the Sergeant), who produced a bravura, strutting performance, with voice, energy and movement to match. Compliments also have to go to set and costume designer Charlie Tymms, who conjured up full period costumes and a combination of painted backdrop and hard building facades that worked wonderfully.

The way the plot is developed may not have the last edge in dramatic intensity, but Hugh the Drover has a good story at its heart, and this production has much to recommend it. In my case, I have to confess, it was always going to be a struggle, because I have serious reservations about the English pastoral genre in general. To paraphrase Jeremy Paxman's argument in The English, the problem with the whole "dancing round the maypole on the village green" theme is that even by the time Vaughan Williams started writing the opera in 1910, the industrial revolution had made certain that such a lifestyle was a distant mirage for the vast majority of the population, and I find the whole thing rather false. If you don't suffer from such qualms, you'll probably love it all, because the music is very good at taking simple, very folky melodies and wrapping them with sophisticated orchestration and modern composition techniques which add interest.

For RVW fans, it's a must-see: his operas don't get performed much, this is a rare chance to see one. For the rest of us, it's interesting at least (an opera of such sophistication based so heavily on English folk music is unusual and maybe even unique, although I'm happy to be told otherwise). And judging by the rapturous reaction, the music will delight many.