Jonathan Larson's autobiographical chamber musical started life as a 'musical monologue', and remains a deeply personal piece that resonates with anyone who's ever been young and creatively frustrated.

There's poignancy too, in that the success Larson himself aspired to would only be achieved with Rent, which premiered shortly after his untimely death in 1996. Indeed, the unheard phone message from Stephen Sondheim that endorses the musical talent of his protagonist, Jon, in the final scene, seems eerily prescient.

The ticking of the title is that of Jon's imminent 30th birthday, his girlfriend Susan's biological clock and an unexpected turn in the fortunes of his flatmate Michael. Like most young creatives, Jon finds himself overtaken by friends who've opted to follow more traditional careers, and his self-doubting is magnified on the eve of a workshop presentation of his new musical 'Superbia'.

Tick... Tick... is not, in truth, a great work – the score is patchy and the libretto rather bland. This is also far from a great revival, played out on an uninspiring white set in an unsuitable two-sided arrangement of the Union's tiny space.

But there is compensation in the performances of Ashley Campbell and Leanne Jones, who as Jon and Susan make a rather unconvincing romantic match but a fine vocal duo – Jones belts out “Come to Your Senses” (from 'Superbia') like an opera diva while Campbell pours himself into emotive numbers such as “Johnny Can't Decide” and “Why”.

The Sondheim worship prevalent throughout invites comparison, and if held up next to Company or Sunday in the Park with George this pulls up rather short. But nevertheless even a lukewarm revival is enough to highlight the painfully unfulfilled potential of Larson.