When Martin Kušej staged Idomeneo at the Royal Opera back in 2014, his use of a rubber shark to represent the sea monster in Mozart’s opera seria drew a fair amount of derision. Stephen Medcalf, in his new production for the Buxton Festival, avoids such a trap by turning the “pitiless monster” into the Cretan king’s mental turmoil, snarling and slavering, a monster of the mind. Given Paul Nilon’s central performance of great dramatic sincerity, it made for a powerful metaphor in a straightforward staging, even if vocal performances weren’t uniformly strong.

Isabella Bywater’s single set features a room which has been engulfed by white sands, drifting up high into one corner, where we initially see Ilia chained to the stone wall. The backdrop tilts and totters to briefly place us on board a ship, where we see Idomeneo slash his palm in swearing his all-important oath to Neptune, promising to sacrifice the first person he sees should the king be spared in the tempest. Some of Medcalf’s direction works well, such as Elettra bristling in the shadows as she spies the prisoners being released. In Act 2, the single items in her suitcase are a wedding dress and veil, revealing her intentions towards Idamante now that Idomeneo has decreed his son must be sent into exile. But cheating the gods can only lead to further complications and things spiral (slowly) until Neptune decrees enough is enough and calls off Idomeneo’s debt, the god speaking through the king’s mouth. However, the staging resorted to yet another tired example of furniture abuse blighting operatic direction, Idomeneo flinging chairs and cutlery everywhere. It’s lazy directorial shorthand.

Musically, this first performance of the run was mixed. Mozart’s score was shredded, losing around 45 minutes of music to squeeze the running time to under three hours (including one interval). Predictably, the ballet music went AWOL, along with both of Arbace’s arias, and much else besides. Even with the cuts, the final act felt tediously long in reaching its resolution. Nicholas Kok drew lean playing and punchy period attitudes from the Northern Chamber Orchestra, the conductor contributing fortepiano recitative accompaniments. The incisive chorus – made up of young singers forging their way into the industry – sang terrifically.

Dressed in shocking pink, Madeleine Pierard sang a terrific, spitfire Elettra, a fearless performance as the spurned love interest. With a warm vibrato, she produced a bitter chocolate darkness to her lower register – the darkest of the female voices on display this afternoon – allied to convincing acting. Rebecca Bottone’s Ilia was bright and gritty, her Act 2 aria “Zeffiretti lusinghieri” needing softer edges. Heather Lowe’s confident Idamante was vibrant, but sounded insufficiently differentiated from her soprano colleagues.

Paul Nilon has a far from sweet Mozart tenor, and Idomeneo’s arduous runs sounded too challenging, leaving him labouring in choppy vocal waters. He husbanded his limited resources well, but lacked tonal colour and fluency. Nilon knows the role intimately and his dramatic experience was telling in Medcalf’s effective staging.