Opera school productions are designed to provide experience for their students and showcase their talents to an audience sprinkled with casting directors. Clearly, the Guildhall School have decided to extract maximum value from their current production by staging not one opera but three, with different casts and even different orchestral musicians. For added interest, they have chosen three short works that were highly successful in their day but have faded from the current repertoire: two romantic operas by Massenet, followed by a surreal 20th century comedy by Martinů.

The works by Massenet both follow the broad theme of his more famous Manon: rich boy falls in love with impoverished girl; boy's father refuses consent; bad things happen. La Navarraise is set during a civil war in Spain in the 1870s; the opening overture is powerful, making it clear that we're in for some serious drama to follow. Anita, the girl from Navarre of the title, is spurned by her sweetheart Araquil's father unless she can bring him a fortune in dowry. She succeeds in earning the money by covertly assassinating the enemy leader, but falls foul of the law of unintended consequences; Araquil is killed and she goes insane with grief. La Navarraise occupies a middle ground between romantic and verismo genres: the basic story, characters and musical style are those of standard romantic opera, while the setting is gritty and distinctly in the verismo world.

Le Portrait de Manon is a strange beast. A sequel to the original Manon, it turns the story on its head by showing us Manon's lover Des Grieux grown older into a hard-hearted father precisely like his own, determined not to allow his ward Jean to throw himself away on the love of the beautiful Aurore (just as Des Grieux threw himself away on Manon, with whose portait he is still obsessed). This gives the cue for extensive lyrical baritone solos from Des Grieux and for some very pretty duets between the two lovers (Aurore the soprano, Jean being a mezzo trouser role). But Massenet can't bring himself to repeat the tragedy, and the whole thing ends happily when Des Grieux's friend Tiberge gets Aurore to dress up as Manon and thus persuades Des Grieux that Aurore and Jean's love is a sacred and unstoppable one. It's a gentle opera which has lovely music but little in the way of genuine drama to set the pulse racing; not the most exciting of sequels.

Stephen Barlow's direction and Yannis Thavoris's sets for all three operas were exemplary: straightforward, visually interesting and adding plenty of atmosphere to proceedings. For La Navarraise, we see broken walls and the pile of junk that constitutes a city riven by warfare; costumes are moved forward to the more recent Spanish Civil War; the overture is heard through bursts of machine gun fire; an angled city wall provides a path around the debris for entrances and exits which makes the movement around stage natural and effective. For Le Portrait de Manon, the shape of the stage is retained while the pile of junk is brilliantly transformed into bric-a-brac in the antiques shop that Des Grieux now owns, in which is buried the larger-than-life portrait of Manon.

But the opera I enjoyed most of the three was Martinů's 1937 Comedy on the Bridge, originally written for radio. The premise is this: we are watching a bridge between the two halves of a city divided by war (in Thavoris's sets, obviously conceived as somewhere on the border between Serbia and Croatia). The border guards on each side are sufficiently obtuse that they allow people onto the bridge if they show the appropriate permit, but they are never allowed to leave the bridge, even to go back to the side from which they entered. As the opera progresses, therefore, a succession of characters get stuck on the bridge, with hilarious consequences.

As ever, Martinů's music is delightfully eclectic: the man can throw in snatches of almost anything into the cauldron, give it a stir and make it into something that's interesting, fun, easy on the ear and well suited to the action. Martial music, ballads, folksong and drinking tunes are all in there. The libretto, adapted by Martinů himself (and sung in translation here), is eccentrically delightful, effectively satirising the coarse obtusity of the military and gently poking fun at the predictable characters of the townspeople. It was a delightful way to close the evening.

One comes to events like these listening out for stars of the future, and several of the voices impressed. The pick of the bunch was Magdalena Molendowska in the title role of La Navarraise: a big, strong, dramatic voice combined with plenty of stage presence. There were imperfections - the odd note that went harsh at the top or missed the middle - but I think Molendowska is going to be one to watch. As Garrido, the general who pays Anita to carry out the assassination, James Platt gave us a strong bass, notably powerful and rich for one of his years. Ben McAteer sang fluently and passionately as Des Grieux, with Raphaela Papadakis giving us a bright and breezy light soprano as Aurore, showing herself well capable of the coloratura tricks in the score. Catherine Backhouse proved an engaging partner in their duets, the voices blending beautifully.

Comedy on the Bridge isn't really a vehicle for showcasing singing voices in the same way; rather, it gives the chance for showing off comic timing and acting skills. There were good performances all round, with Samantha Crawford making the most of her central role as Popelka the village beauty and James Platt showing that he can do comedy as well as his serious role in La Navarraise. Frazer Scott and Adam L Sullivan also set the scene splendidly in the spoken roles of the two border guards.

Orchestral performances were a bit patchy. La Navarraise had plenty of excitement, but suffered from problems both in intonation and timing. These were improved in Le portrait de Manon and the orchestra seemed considerably more comfortable with the more varied and less sweeping tones of the Martinů. All in all, an interesting and varied evening, excellent in production values if short of the highest musical and dramatic levels.