In terms of serious subject matter, Roger Crane’s The Last Confession is about as heavyweight as it gets: the mysterious death of Pope John Paul I after only 33 days of his papacy is a controversy that still haunts the Catholic Church, and is certainly not a subject lightly to be taken up. Though I appreciate Harry Sheehan’s directorial ambition in wanting to stage this monolithic play, his production is insipid and amateurish, unable to revive the full force of the Vatican maelstrom.

The play follows Cardinal Benelli’s final hours when, racked by unspeakable guilt, he  remembers the recent papal scandal, convinced of his own complicity in hurrying the late Pope to his untimely death. Lewis Owen gives a sensitive though vitally limited Benelli: while I was wholly convinced by his moral turmoil and disillusionment with the Church, his remembered self showed no sign of the ambition for which his current self was so regretful. However, Owen’s performance matured immensely over the course of the play, steering clear of mawkishness, and giving the production a firm grounding.

Yet for a play about the papacy, Sheehan’s Popes are underwhelming: Tim Squirrell’s John Paul I was only marginally more charismatic than Alex Brown’s John VI, both of whom are suitably softly-spoken, but with no iron fist beneath the velvet glove. This grants a predictability to both Popes’ pulverisation by the Curia and flattens any suspense, leaving the play to plod meaninglessly towards its end.

Ultimately, the play’s hefty subject matter demands from the cast a deftness and precision which they cannot bring: performances too often veer towards the inappropriately frivolous (Squirrell’s "Damn them!" had the unfortunate ring of a Carry On film) or emotionally constipated. The size of the cast made it difficult to properly nuance each part, making many of the Cardinals seem hopelessly caricatured: Stefan Nigam’s sneering superciliousness quickly stales onstage, whilst Paddy Howell-Day’s incessant shouting becomes overbearing. On top of all this, the play has no clear narrative focus, torn between Benelli’s guilt and the ecclesiastical scheming in which he is embroiled, neither of which are fleshed out to any real degree of profundity.

In its defence, the scope of the drama is impressive, the cast enormous, the staging stark and majestic. The play is nothing if not thought-provoking: one cannot help but shiver at Benelli’s "What if there is nothing?" or Pope John Paul’s "The Pope is always alone". However, the performance is often let down by detail - line-fluffing, glitchy lighting and staging malfunctions (at one point the curtain had to be held back manually) - and as the play draws to a close, lines are reeled off mechanically. The silence with which The Last Confession leaves its audience is not loaded with papal fallibility and ecclesiastical corruption, but empty, confused and uncertain.

The Last Confession runs until Saturday at the Fitzpatrick Hall, Queens's College, at 7.30pm