One of Barbara Pym’s later novels, The Sweet Dove Died is known as being less overtly comic than her other works, and all the better for it. And that makes it such a pity that this musical adaptation, renamed after a line from a Keats poem, struggles so comprehensively to tell a coherent story.

Ostensibly the tale of middle-aged socialite Leonora (Francesca Ellis) and her obsessive interest in Ryan Frank’s James, a dashing young assistant in his uncle’s antiques shop, director, lyricist and book writer Joe Giuffre chooses to portray the setting of swinging 1960s London solely through archive film footage projected onto a backdrop behind a large, bare stage, the only set being three groups of nondescript, modern chairs.

The minimalist approach – which stretches to a lack of any props, reducing the cast to miming various dining and drinking opportunities – could work if the characters had enough interest and pace to sustain interest. Unfortunately, save for Ellis’ dry delivery bringing out some of Pym’s trademark comic wit, Giuffre’s adaptation reduces each character’s persona to the bare minimum, removing any opportunity for emotional connection with the story or the people within it.

Juan Iglesias’ music, in contrast, is evocative of the era, evoking the spirit of Burt Bacharach or, especially in the show’s eponymous final number ‘The Mirror Never Lies’, John Barry’s Bond themes. But Bacharach needed his Hal David, Barry his Leslie Bricusse, to complement the music with lyrics to match – and with the best will in the world, Giuffre’s lyrics fail to inspire.

Matters aren’t helped by a series of odd choices as to which plot moments should be marked in song, and which shouldn’t. As James is pulled between Leonora, his girlfriend Phoebe (an under-utilised Jennifer Harraghy) and his uncle’s demands that he moves to New York for more training, for example, what could have been presented with emotion is instead delivered as two near-identical farewell conversations with the women in James’ life.

Undoubtedly the actor who draws the shortest straw is Ryan Frank, making his professional debut as James. While he does a nice line in bumbling English foppery, and gets to nail one big solo number (the closest the musical comes to an ‘I want’-style number that would inform the audience as to what the point of the whole story is), he is otherwise reduced to playing a character that is completely reactive.

His uncle, Leonora, Phoebe and the assertive Ned (Spencer O’Brien trying his hardest with a poorly written predatory homosexual) all decide how James is to fit in with their own plans, with the character himself having no agency. A more deft directorial hand may have been able to make something of this theme: all we see here is a leading man whose passivity provides yet another barrier to audience engagement.

Together with some other poor choices – such as a baffling early dinner scene with Leonora’s friend Meg (Darrie Gardner) that seems to offer little in the way of plot or character progression, or having Jon Osbaldeston’s lascivious antiques dealer indicate his crotch every time Giuffre’s lyrics give him another blindingly obvious double entendre – all these flaws can’t help but add up to make The Mirror Never Lies a poor adaptation of Pym’s novel.

There are elements to admire – from Iglesias’ music (well crafted by MD Joseph Finlay) to Ellis and Frank’s performances – but ultimately, in its failure, this production serves mainly to show how difficult it is to create a good musical.