An undiscovered Noël Coward play? Sounds intriguing and delightful. Will it have the sparkling wit of Private Lives? The horseplay of Hay Fever? The high comedy of Blithe Spirit? Those plays were written when Coward was still a gay young thing, and when he could see every aspect of human life through bright and risqué eyes whilst still reflecting the truth about society. But Volcano – unperformed in Coward’s lifetime – was written in 1956 when the gay young thing had become a gay older thing and, perhaps with a nod to the tough lives being portrayed in the contemporary plays of Osborne and Wesker, this is a much more serious play.

And, for me, that’s its problem from the start. I don’t think Coward does serious very well, unless it’s of the patriotic “In Which We Serve” or “This Happy Breed” kind. This is a play full of downbeat and dismal relationships. Adela was happily married but now widowed, and takes the view that happiness is past and can never return again. Guy is serially unfaithful to Melissa, whose coping strategy is to employ her natural snappy toxicity. Ellen and Keith are on the rocks and will probably only stay together for the child’s sake. The only characters who seem to make a plucky go of their relationship are Grizelda and Robin, but Coward has relegated them to the sidelines as far as the real meat of the story goes. Overall, it’s extremely pessimistic about love and relationships.

But these are real problems – and according to the programme, based on the experiences of real people that Coward knew at his Jamaican hideaway – Ian & Mrs Fleming no less. So this ought to form a gritty account of relationship problems that you can really get your teeth into. Centre stage, and acting as a metaphor for a seething cauldron of emotions, is the volcano up against which Adela’s house is perched. Unfortunately, despite the potential intensity and depth of the characters’ situations, the play just doesn’t take off and the volcano is reduced to something of a molehill. It felt to me as though the text were just a first draft of something that could have developed into a more satisfying final product. By the second draft the plot would have had more intrigue and by the third he would have scattered it with bons mots and enhanced linguistic dexterity; but as it stands, it’s a bit like Norfolk – largely rather flat. That’s not to say there aren’t some good scenes, there are; Ellen’s two second-act confrontations with Melissa and Keith are full of surprises and very well played; and Melissa’s conversations throughout are spiky and acerbic. But I also felt that many of the speeches were written more like erudite prose than believable conversation. If the author had been alive I am sure there would have been subtle rewrites during rehearsals that would have made the whole thing flow better; not an option forty-odd years after his death, I realise.

Director Roy Marsden and designer Simon Scullion have gone for a very naturalistic presentation of the house and volcano. This means the representation of the volcanic eruptions, with the sound and lighting effects and subsequent destruction of part of the set, have to be very naturalistic and believable too; and with the best will in the world, it’s a big ask. Some minor pyros and flickering lights that dislodge at an angle of 30 degrees doesn’t quite suggest terrifying semi-devastation to me. The next morning after the eruption, Adela goes around cleaning up the garden and washing all the black soot off the chairs and tables – she refers to the dirt and dust a few times in her speeches – but you can see that her cleaning cloth is as free from lava residue post-wash as it was before. That also contributed to the lack of credibility of that big central stage effect. To be honest I think the whole thing would have worked better in a smaller space – somewhere like the Menier or the Sheffield Crucible Studio – with much less in the way of intricate stage design and demanding greater reliance on the audience’s imagination. That intimacy might also have made the character interaction more telling.

Adela is played by Jenny Seagrove, who I haven’t seen before on stage. She gives a good impression of a strong-minded and intelligent woman reining in her emotions, but vocally I found her delivery rather samey throughout; the tone she used to address Ellen when they were remembering good times and her tone of disappointed anger with her in the second half were pretty much identical, for example. In fact the only time she actually sounded enthusiastic was at curtain call when she was encouraging us to donate change to her new animal welfare charity on our way out of the auditorium; a gentle form of chugging that felt strangely inappropriate given the time and place.

Jason Durr as the licentious Guy subtly underplayed the role I thought – he could have been more over-the-top with his protestations of love and general spoiltness, but instead made the character more credible and realistic. No doubt this was the role that Coward would have played himself. As Melissa, his justifiably bitchy wife, Dawn Steele probably has the best lines in the play and she too could have played it more savagely and ostentatiously at the expense of credibility, so that was a very thoughtful interpretation I felt. The other members of the cast all gave good solid performances.

But I’m afraid both Mrs Chrisparkle and I found the whole thing rather boring. In fact I had to look sternly at Mrs C when she lightly suggested skipping the second half. It wasn’t that bad. Apparently Coward wanted Katharine Hepburn to play Adela – she turned it down, and I can see why. Gertrude Lawrence had died four years earlier; if he’d written the role of Melissa for Miss Lawrence the character would probably have been both more adorable and spiteful which might have made the play punchier. Regrettably, as it stands it lacks dramatic intensity and drive. Fascinating to see it, of course, to complete one’s knowledge of Coward’s oeuvres; but essentially disappointing.