What is Beethoven’s only opera Fidelio about? Yes, I know the story tells how Leonore disguised herself as a youth to get into the prison where her husband is being held and, she discovers, starved, but what is it about?

The corruption into which even revolutions with the best of intentions may fall? Opera North’s concert performance, live-streamed from Leeds Town Hall on 12 December and available on demand until 23.59 GMT on 19 December, uses the framing device of Don Fernando, of the Truth and Reconciliation Committee, recounting his investigation, including excerpts from the report of the jailer Rocco, to fill in the spoken dialogue which has been cut.

Love? Sure, junior jailer Jaquino is pestering Marzellina, daughter of Rocco, to marry him, but she has fallen for Fidelio, aka the disguised Leonore. In turn, Rocco is happy to let his daughter marry this fine young man, while the ‘fine young man’ is feeling really bad about the deception but cannot, yet, reveal her identify.

‘Mir ist so wunderbar' works well with social distancing, Matthew Eberhardt spreading the soloists across the front of the stage in their own little bubbles. They are all dressed in black which, while fitting, and allowing non-singers to fade into the background for a while, is a bit unrelieved, especially with the quite sombre lighting designed by Mike Lock. .

Oliver Johnston is ardent as Jaquino, and Fflur Wyn’s Marzelline leaves us in no doubt exactly what would have attracted him. Brindley Sherratt convinces us that Rocco is not a bad man, though he obeys orders he is not entirely happy with. Robert Hayward, on the other hand, is splendidly bitter and twisted as Don Pizarro, the prison governor and determined to have his revenge on Florestan. Matthew Stiff is the voice of reason and justice as Don Fernando, the only character in costume, wearing judicial robes.

Up close on camera, it is easy to see the pain and sorrow in Rachel Nicholls face, as she works through the wide range of Leonore / Fidelio’s emotions. Toby Spence, looking remarkably hale and hearty for someone starving to death, is in the depths of despair in his dungeon.

There is a poignancy when the prisoners emerge into daylight, each in their separate space. The chorus and orchestra, under the direction of Mark Wigglesworth, are expressive, and the oboe duetting with Florestan, when he hallucinates his imminent death, is delicate.

When all is finally resolved, and Don Fernando’s arrival is in the nick of time to prevent Don Pizarro killing Florestan, the quintet with chorus ‘O God, o God, what ecstasy!’, in which all are singing substantially the same words, contrasts with the cross-purposes of ‘Mir is so wunderbar’.

And perhaps that is what Fidelio is ‘about’. In this year, when so many of us have felt imprisoned by greater or lesser lockdowns, we recognise the pain of the restrictions on the characters and.as the programme notes remind us, by the time Fidelio was premiered, Beethoven was already imprisoned in increasing deafness.