The Alchemist, NT Olivier, London <br/> Pravda, Festival Theatre, Chichester <br/> The Madras House, Orange Tree, Richmond

You need some kind of catalyst to turn The Alchemist into 24-carat theatrical gold. Combining Simon Russell Beale and Alex Jennings - two of the NT's best-loved stars - ought to do the trick in Nicholas Hytner's new production. Ben Jonson's Jacobean comedy, about lowlife tricksters who fleece a string of gullible fools, is certainly a challenge. At once comparable in its set-up and less arresting than the same author's Volpone, it's peppered with arcane argot and technical terms from alchemy. The rogues, Subtle and Face, pretend to be on the brink of discovering the Philosopher's Stone which will, supposedly, turn base metal into gold and bless those who get their hands on it with eternal youth.

Hytner's solution is not just to cast those leading roles strongly but also to update the action so that Jennings's Subtle and Russell Beale's Face are modern scammers ripping off suckers in 1960s-going-on-present-day London. Thus, when Subtle poses as the master alchemist he firstly dresses up as a fey hippy guru - all beads and Lennon-style dark glasses. Ringing the changes, he adopts two other personae as well: a prissy cult leader who pockets donations while swanning round in a white cowl and a more deceptively traditional, tweedy doctor.

The directorial concept highlights how conmen and credulous idiots, in some ways, never change. The corner-shopkeeper, Amit Shah's Abel Drugger - who seeks advice about where he should place his door for best profits - could just as well believe in feng shui as necromancy. There are more cheeky contemporary twists too (including some ad-libs). Tristan Beint's Kastril, a public-school twerp who's being primed in the grammar of quarrelling, launches into streams of insults with the rolling swagger of a wannabe rapper. More generally, Jonson's portrait of a society undermined by selfishness and greed applies to current times.

However, this is not Hytner's most successful modernisation. It often feels mildly strained, lacks real bite and is not quite thought through, actually missing a few tricks. For instance, to believe that the disguised prostitute, Lesley Manville's Dol, is the Queen of Faery, the smart-suited lawyer's clerk, Dapper, would surely have to be on drugs (which could easily be intimated).

This production will, I suspect, get funnier. At the final preview which I attended, Ian Richardson's Sir Epicure Mammon, luxuriating in wanton fantasies, kept falling disappointingly flat and Jennings's gamut of accents (from American to Scots) isn't all that hilarious. Nonetheless, Tim McMullan is splendidly silly as a swishing mock-Spaniard and Russell Beale is, as always, outstanding, with dry comic timing and moments of terrific flamboyance - staggering like Frankenstein's Igor out of an exploding laboratory. He also imbues Face with disturbing psychological depths, almost Iago-like festering jealousy and unloved misery.

It's been a week of wheeler-dealing with David Hare and Howard Brenton's 1985 newspaper satire, Pravda, getting a major revival at Chichester. Roger Allam plays Lambert Le Roux, the media mogul who - with some veiled allusions to Rupert Murdoch and Robert Maxwell - muscles into Britain from South Africa, starts buying up tabloids and broadsheets, strikes mutually beneficial deals with MPs behind the scenes and turns decent journalists into compromised trash-mongers.

In certain respects, Pravda now looks like yesteryear's news: a period piece featuring typewriters and hacks in trilbies. But this damning vision of the industry also had foresight, particularly ringing alarm bells about the dumbing down of the British media. The co-authored script can feel sketchy, but that's partly because Jonathan Church's ensemble are too stylistically uneven, some sticking to naturalism as others swiftly opt for caricature. La Roux is not as alarmingly monstrous here as Anthony Hopkins's hulking toad of a tycoon was in the original NT production. Allam looms smaller, is bullish but without so much menace. In the long run, however, perhaps he is the more worrying for being life-sized. Church's big-cast productions are financially brave and worth catching.

Finally, the reclaiming of Harley Granville Barker's plays continues with The Madras House, staged by Sam Walters. This makes an interesting pairing with HGB's The Voysey Inheritance at the National, depicting another well-to-do Edwardian family embroiled in business deals and scandals. An additional frisson arises as the prodigal brother, Richard Durden's Constantine, returns from abroad as a convert to Islam. That said, this play is hard work. The family's trade may be haute couture, but the dramatist leaves narrative threads trailing. The arguments about feminism and the effeminising of society are also frustratingly male-dominated, verbose and lacking in lucidity. Still, that doesn't stop the play's shifting sympathies being curiously unsettling, leaving you still mulling it over days later.

k.bassett@independent.co.uk

* 'The Alchemist' (020 7452 3000) to 21 November; 'Pravda' (01243 781312) to 23 September; 'The Madras House' (020 8940 3633) to 14 October