Cabaret, Lyric Shaftesbury, London; King Lear, Barbican, London

We are, right now, being bombarded with scenes from the Weimar Republic, the decadent 1930s democracy facing the rise of Fascism. Hot on the heels of last week's West End production of Bent, we have Rufus Norris's major revival of Cabaret, the celebrated Kander and Ebb musical based on Christopher Isherwood's tales of pre-Second World War Berlin which, of course, revolves around the saucy Kit Kat Klub. Here we see an uptight bisexual ex-pat called Clifford (Michael Hayden) temporarily relaxing and falling in love with the incurably boho chanteuse, Sally Bowles (Anna Maxwell Martin).

At the off, one can't help observing that this Weimar trend certainly entails stacks of flagrantly bare bottoms - which, I guess, will be a big thrill for some. James Dreyfus's Emcee is a leering drag artist of the Grand Guignol-going-on-Ann Summers school: ghoul-faced with suspenders and that well-worn titillator, the nipple-crested corset. The chorus line likewise incline toward scant pants and spanking. Choreographed by Javier De Frutos, they get swinging in a markedly direct fashion, flipping each other over with forthright grips, hand-to-crotch.

Dare I say it, though, a few in-yer-face buttocks go a long way. This Shaftesbury Avenue production really isn't Norris at his exhilarating artistic best and overall, the evening falls slightly flat. Perhaps having everyone living in a gloomy expressionistic bunker from the outset is a premature downer. Norris also leaves several of the solo songs - including Sally's "Maybe This Time" - drearily static. On press night, Maxwell Martin didn't look as if she was enjoying herself at all. This role, alas, exposes her limits. She does have a slinky silk outfit and flashes of affectionate sweetness, but she's not got much of a singing voice and she seems peculiarly tepid for a sexually hot ticket. The emphasis is so heavily on her Sally being deeply unhappy, that one hankers for the compensating wild, fun side of Liza Minnelli in the classic film version. The accents are all over the place as well. Norris's German folk have a ridiculously infirm grip on their nationality. Meanwhile, Sheila Hancock's Fraulein Schneider - Clifford's aged landlady - is just too sugary. Her shrugging number "So What?" needs more edge, foreshadowing her ultimate moral cowardice - not wedding her devoted lodger, Herr Schultz, because he is Jewish in dangerous times.

Still, Cabaret is food for thought with its anxious portrait of a wantonly self-absorbed, liberal society carelessly dancing its way to destruction and letting xenophobia creep in en route. Taking a lone stand against the Nazis, Hayden's Clifford gains a dynamic feverishness, and Norris's production builds to a politically chilling vision. The deceptively innocent Aryan folksong, "Tomorrow Belongs To Me", is initially accompanied by an Edenic vision of naked souls. At the end that same group, stepping out of the Kit Kat Klub, huddle in a grey whirl of snow as if in the yard of a death camp. By way of a postscript, I should probably explain - in case anyone only familiar with the film is puzzled - the stage musical's subplots are completely different from the movie's.

King Lear, as performed by the world-renowned Maly Drama Theatre of St Petersburg, should come with a similar warning. This is not the Bard's tragedy of old age as we know it. Check out the English subtitles and you might in fact wonder if director Lev Dodin and Dina Dodina - who has provided the company's new Russian translation, so-called - have suffered some senior moments of their own. Many speeches are reassigned or relocated and chunks aren't by Shakespeare at all. Lear's possibly sexually abused daughters have developed a habit of repeatedly crying, "Father! Father! Father!" Edmund reiterates his "Now, gods, stand up for bastards!" line in coital scenes with Goneril and Regan, and Lear's potentially healing sleep is played out as a weird little hallucinatory ballet, where he twirls his three girls as if they're string puppets. Dodina is, frankly, teetering here on becoming the Thomas Bowdler of our time.

Declan Donnellan's recent, comparably radical reworking of Twelfth Night, with a Russian cast, was far more sensitive. Nevertheless, it is a shame that this roduction's planned UK tour has been axed. Dodin's ensemble acting is outstanding and fiercely impassioned. Set in a rough-hewn barn of a palace, his take on Act One's often stiff, kingdom-dividing scene is remarkably funny. Petr Semak's ponytailed Lear shuffles through the auditorium in a white gown and wooly socks, perhaps already senile with a voice that cracks easily, but still a master of teasing power games. He goes on to stage-manage his own abdication from a throne resembling a film director's chair, turning round to wryly eye the audience reaction to his children's declarations of devotion. And all this is accompanied by his Fool who plays flurries of sardonically jaunty, silent movie-style music on an old piano.

As he spirals into destitution, Semak becomes poignantly vulnerable, like a devastated little boy, and he dies alone, with no stately entourage. Danila Kozlovskiy's Edgar is also harrowingly agonized, hugging his suicidal blinded father, and Goneril and Regan - far from malignant monsters - are tearful and torn between love for their father and long-suppressed exasperation, having to really gird themselves to overthrow his dominance. All in all, flawed but sometimes brilliantly insightful.

k.bassett@independent.co.uk

* 'Cabaret' (0870 050 0511) booking to 7 April