Don Alfonso (Big Donnie to you) rapped his way up the aisle and gave me chocolate. Was it a bribe? He was clearly capable of anything — and his real name was, aptly enough, Paradise. And, as MC, he controlled a Cosí fan tutte such as Glyndebourne has never seen before.

That this hip-hop reinvention of Mozart’s opera tapped into its tenderness, violence, passion and despair more powerfully than almost any Cosí I’ve seen was testimony to its success. With 18 young Brighton teenagers involved on stage, School 4 Lovers is an extremely classy act. From the graffiti-lit cityscape of Robin Carter’s design to the playing of the Southbank Sinfonia under Jonathan Gill to the outstanding performances of both classical and rap artists in Clare Whistler’s artfully paced production, this is one of the slickest and sassiest musicals around.

The notion of morphing Mozart into the voice of an inner-city prophet seemed risky in the extreme. But it has worked. And the sheer virtuosity of those metamorphoses in the musical arrangements of Charlie “The Baptist” Parker and Jonathan Gill is striking, sometimes breathtaking.

At times the orchestra cunningly fragments Mozart’s harmonic progressions into Nymanesque minimalist patterns, propelling the rap. And then time stands still, as Cosí’s great terzetto of parting (“You’ll text me every day”, aka “Soave sia’il vento”) is cast into pulse-stopping relief.

The updated story has spawned a text from Stephen Plaice that Mozart would have relished. As an accomplished jazz singer, Natasha Seale (Despina) has extra numbers of her own; Jessica Walker’s Gigi and Christine Gelder’s Bella are vividly individualised; and although Ville Salonen’s Freddie strains to meet all the demands of Ferrando’s music, Marvin Springer’s Liam is a virtuoso Guglielmo.

The choreography of Paradigmz could have drawn still more energy from the youth crew, and the Lyrical Prophets Rap Crew also, I felt, had their wings clipped. But this School 4 Lovers will be a hard act to follow.