Pairing Mascagni’s Cavalleria Rusticana with Gilbert and Sullivan’s Trial by Jury makes for a pleasingly schizoid evening in the latest of Opera North's The Little Greats series. Mascagni’s crashing final chords precede a longish interval, and when you re-enter the auditorium it’s not just the set that’s changed, but much of the audience.

The first day of rehearsals for The Little Greats was thrilling and terrifying in equal measure: the casts of six shows, the whole chorus, all the creative teams and management milling around and talking nineteen to the dozen in the big, reverberant Linacre Studio at Opera North. Old friends, new colleagues – it was like a mixture of freshers’ week and a first night party. The noise was stupendous.

I’ve said it before and I’ll say it again: you have to be pretty silly to take Gilbert and Sullivan seriously. But even sillier not to.

Men playing boys playing girls, women and men, all female parts convincingly falsettoed and high musical standards as backbone: Sasha Regan's single-sex Gilbert and Sullivan has worked a special magic on Iolanthe and The Pirates of Penzance, HMS Pinafore and now The Mikado, not so much. Energetic song and dance are still in evidence.

How well do you know your bad Victorian poetry? “When through the purple corridors the screaming scarlet Ibis flew/In terror, and a horrid dew dripped from the moaning Mandragores.” Go on, guess the author. Or how about this? “What time the poet hath hymned/The writhing maid, lithe-limbed,/Quivering on amaranthine asphodel". Got it yet? The first is Oscar Wilde’s The Sphinx, from 1881. The second, WS Gilbert’s libretto for Patience – written in the same year, and skewering Wilde with gleeful relish and lethal precision.

"Oh what a beautiful morning! Oh what a beautiful day!" Curly the cowboy sang in the opening scene of Oklahoma!, the first musical from Rodgers and Hammerstein (1943). In the midst of war here was sheer optimism and celebration set – with some nods at reality ("there’s a bright golden haze on the meadow, the corn is as high as an elephant’s eye, an’ it looks like it’s climbin’ clear up the sky") – in the American West.

It should have been unmodified rapture: a gathering of English National Opera team members old and new celebrating the doyen of the company's best-selling productions. And, as has always happened with the artistic side of the company, this loving homage to Sir Jonathan Miller sounds like a triumph. Critics weren't invited to the gala - statement, not sour grapes; this was a charity event, after all - and the final rehearsal was closed, though not apparently at the wish of anyone performing. The circumstances, though, tell us a lot about a company divided.

By the end of Act One of The Yeomen of the Guard there's been a jailbreak, a clandestine marriage, a swapped identity and a cancelled beheading. The chorus sings, halberds are brandished, and a jester jests. Even by Gilbert and Sullivan standards, it’s one heck of a tangle. And then, in John Savournin’s touring production, the stage clears and, true to Gilbert’s directions, Elsie faints in Fairfax’s arms while silhouetted behind them, masked and motionless, stands the grim figure of the executioner.

Ilya Beshevli: Wanderer (Village Green)

How ironic that English National Opera turned out possibly the two best productions of the year after the Arts Council had done its grant-cutting worst, punishing the company simply, it seemed, for not being the irrationally preferred Royal Opera. And while 2015 has been as good as it gets artistically speaking for ENO, 2016 may well see confirmation of the first steps towards its dismantling by a short-sighted management – for what is a great opera house without a big chorus or a full roster of productions, both elements under threat?