An Enemy of the People, Crucible Theatre, Sheffield<br/>A Midsummer Night's Dream, Rose Theatre, Kingston<br/>Serenading Louie, Donmar Warehouse, London

The new regime at the revamped Crucible gets off to a flying start with scorchingly relevant Ibsen

One of Britain's most celebrated regional theatres, the Sheffield Crucible, has just been refurbished at a cost of £15.3m. You might expect something showy for that money, but the place looks largely the same. Is this sorely disappointing? Actually, no.

Declining to be flashy has to be admirable in these straitened times. What's wanted is quality work, and that's just what the Crucible has come up with. The new regime of actor turned artistic director, Daniel Evans, gets off to a flying start with his production of An Enemy of the People, Ibsen's still trenchant 1880s portrait of financial corruption and the failings of democracy.

As the maverick doctor and scientific adviser who reveals that his town's lucrative spa has been polluted by its factories, Antony Sher positively bounds towards his doomed battle with his brother, the mayor – John Shrapnel's fuming Peter. At the start, Sher bounces around like a jovial gnome in sideburns (modelled on Ibsen's own). Welcoming the press and leading tradesmen into his family home, he beams with scatty bonhomie and brims with naive optimism about how his exposé of this health-endangering blight will lead to instant improvements.

By the end, he's reduced to a suicidal pariah, because what he's really discovered is that the entire capitalist system is rotten to the core. From the political leaders to the workers, everyone wants to bury the bad news, to protect their incomes.

Evans's cast could perhaps sharpen those moments when the ulterior motives – on all sides, in this conflict – are laid bare. Yet by playing down malignant cunning, the production avoids melodrama. Sher and Shrapnel excel in bringing out the explosive comedy of the brothers' face-offs, throwing themselves into bouts of fisticuffs. And in the town hall, before a baying mob, the good doctor's climactic rant about the stupidity of most people and the disastrous consequences for democracy, and about a culture that dismisses expert opinion, is electrifying. It's also shockingly brave, appallingly funny, and insanely elitist.

Given that Evans's directorial CV has boasted only small-scale shows up to now, this is a terrifically assured major production and a promising fresh start for the Crucible. And that refurbishment? Well, it's enough to say that the foyers are almost endearingly unpretentious, with their 1970s breeze blocks left untouched (they're listed, in fact) and their carpeting barely distinguishable from the original. Shifting the box office and bars has made the building feel airier. It is also more wheelchair accessible, less noisy and emits less carbon. Meanwhile, the auditorium has subtly comfier seating and an improved lighting rig. That money was well spent.

Moving seamlessly from one national asset to another, Judi Dench twinkles in the gloaming as the fairy queen in Peter Hall's new staging of A Midsummer Night's Dream. In high-piled ginger curls, starched ruff and ropes of pearls, her Titania looks like the elfin twin of Elizabeth I (who Dench memorably played in the film Shakespeare in Love). It may seem odd to draw allusions between this sprite – who deludedly takes Bottom the ass to her bed – and England's Virgin Queen. But, of course, The Dream takes us into the woods of the unconscious where, for just one night, frustrated desires run wild. Supporting this view, Hall's programme notes remind us how Elizabeth loved to flirt even in old age, according to Lytton Strachey's biography, "filled with delicious agitation by the glorious figures of men".

At first, though, Dench's Titania is frostily regal, riled by Charles Edwards's Oberon who – in being her junior but trying to throw his weight around – could be seen as the equivalent of Elizabeth's rebellious favourite, the Earl of Essex. Outwardly, his Oberon is a smoothie who smirks as he smears Titania's eyelids with his vengeful aphrodisiac. Yet his voice cracks with insecurity and self-doubt; he knows in his heart that he's hurting himself.

Hall's production has shortcomings. Though the verse-speaking is commendably lucid, some younger cast members are overemphatic, as if we're all a bit dim, or deaf. The forest could be more enchanted, and Reece Ritchie's Puck, scampering and squealing like an overgrown kid, is pestilently unfunny.

But the mechanicals are all sweetly hilarious. Oliver Chris's eager, youthful Bottom hams up his twitching death scene stupendously in the am-dram "Pyramus and Thisbe". And back in the forest, Dench's fond delight in his towering, gauchely braying incarnation as an ass is completely charming. She strokes his furry ears and snuggles into his broad shoulder with an innocent joy that's ineffably beautiful – and eternally girlish.

Serenading Louie, by comparison, fails to touch the heart profoundly. Lanford Wilson's portrait of two middle-class American couples suffering mid-life crises – having affairs and quietly cracking up – ought at least to be engrossing, and Simon Curtis's chamber production, set in brown 1970s suburbia, has the right claustrophobic bleakness, and a superb slow-burn performance from Jason O'Mara. But given the slice-of-life style, the characters' asides to the audience seem superficial, glued on. Charlotte Emmerson struggles to make Wilson's broken sentences sound like a nervous breakdown, and conversations ramble till you, too, are bored witless.

'An Enemy of the People' (0114-249 6000) to 20 Mar; 'A Midsummer Night's Dream' (0871 230 1552) to 20 Mar; 'Serenading Louie' (0844 871 7624) to 27 Mar and touring

Next Week :

Kate Bassett catches Iain Glen's directorial debut, both staging and starring in Ghosts – another Ibsen