Dark Earth/ The Straits/ The People Next Door, Traverse<br></br>Islands in The Stream, St Stephen's<br></br>Hurricane/ Janet Street-Porter: All the Rage!, Assembly Rooms

Edinburgh theatre: Between a rock and the Scottish deep south

I'll be in a festive humour in a moment, but feel bound to begin in a high dudgeon. The Traverse is supposed to be the Fringe's most reliable professional theatre. But it has patently failed to allow time for all the set changeovers in its rep programme, so every show I attended in the main house this week kept its audience standing around - for nearly half an hour in one case. And the knock-on effect is that festival-goers are missing shows at other venues. I'm developing a conspiracy theory, but in the meantime I suggest everyone send their wasted tickets, in protest, to the Traverse which appears to be deaf to the bad word-of-mouth they are provoking.

That said, their productions have almost all been worth the wait. Dark Earth, David Harrower's new play set in the remote Scottish Lowlands, proves to be a tense, bleak and surprisingly humorous drama by the author of Knives In Hens. A young corporate couple from Glasgow break down in what might be dangerous redneck country. A lane recedes rapidly into the distance, hemmed by a high stone wall. As the irascible Euan jogs off to hunt for a telephone, Valerie finds herself face to face with Petey, a local who remarks without cracking a smile that he'd like to be under her bonnet. Meanwhile Euan has reached Petey's isolated farmstead and is fending off the cups of tea offered by Ida. The city folk end up staying the night, their talk lubricated by whisky. But the hosts' surly daughter, Christine, is one of several spanners in the works, with her eye on Euan.

This might sound like a rural Gothic cliché or a medley of the Rocky Horror Show meets Sam Shepard. But what's fascinating is the mercurial complexity and half-exposed tenderness of Harrower's characters - especially in Philip Howard's production where all the acting is quietly superb. Jimmy Yuill's stocky, bearded Petey is grippingly sinister, as he gazes past Frances Grey's perky Valerie into the middle-distance. Or is he teasing her - you can never be quite sure - with a sophisticated humour that's warm though stony-faced? The family relationships prove richly ambiguous too, with deep-rooted fondness underlying sharp jibes. Harrower explores broader social divisions by making Petey a bankrupt farmer and by having Christine be passionately informed about the region's history, Bonnie Prince Charlie and those who failed to support him. This is worked in fairly smoothly, and the climactic bust-up steers just clear of melodrama.

Also excellent is The Straits, Gregory "Gagarin Way" Burke's second play staged by Paines Plough. In this rite-of-passage tragedy, four teenagers from low-ranking British military families are stuck in Gibraltar in 1982. James Marchant's shorn, swaggering Doink can't wait to join the Marines, like his brother who's fighting the Falklands War. His quieter best mate Jock (Stephen Wight) says he'll follow suit. Meanwhile they're basking down at the harbour, planning to show the local "spics" who's boss in the inevitable clashes of Anti-English Day. However, the immediate victim of Doink's need to prove his machismo is the nerdy new arrival, Darren, who's under the thumb of his big sister.

The Straits is not as wittily bold as Burke's debut which welded socialist philosophising on to a mafia heist. But this is a more refined study of peer pressure, suppressed attraction, aggression and nationalism. There are a couple of jolts in the plot and John Tiffany's production too obviously invokes Frantic Assembly's Tiny Dynamite. But it's electrifyingly choreographed by Steven Hoggett, with tetchy sunbathing danced out like a time-lapse film. Neil Warmington's powerfully stark set is a concrete rock in the shape of a cross, and Tiffany's young actors are fine-tuned. Marchant, in particular, is hair-raisingly vicious and vulnerable.

Over at St Stephen's the shaven-headed, cadaverous clowns of Derevo (from St Petersburg) present their latest physical theatre/ dance spectacular. Islands In The Stream is a fantasia about marine life. Comic and gloomy skits flow into one another, looking stunning in monochrome. Elegant ladies and captains promenade with what should be dogs, only they're cut-out ships on sticks. A young lad in a sailor suit chases a girl who jiggles and flitters like a butterfly. Elsewhere hunchbacks in grey overalls, like sea slugs, slowly roll their cargo: a huge soft ball that suggests a breast or magnified egg. Derevo's images are haunting but their ideas can be a derivative hotchpotch. Something also grates as their ascetic company image doesn't quite tally with their readily exportable, crowd-pleasing shows.

Henry Adams new play, The People Next Door, is lightweight too. Though it touches on post-9/11 terrorism, anti-Muslim paranoia and police corruption, this is really a cute sitcom about a flailing cokehead called Nigel who, having been forced to infiltrate a mosque, discovers the peaceful side of Islam and forms a cuddly community with his council-block neighbours. The start drags as we get more blathering from Nigel than narrative progress. However, Adam has an ear for chat. Roxana Silbert's production offers explosively funny moments, and Fraser Ayres' Nigel can be hilariously weedy and wired, slithering into a his sleeping bag like greased lightning.

Alex Higgins is also reincarnated and spinning like a whirlwind in the one-man tour de force, Hurricane, by Richard Dormer. Occasionally this writer-performer looks histrionically camp as he turns the former world snooker champion into Pot Black's strutting answer to Mick Jagger. But he dramatises the story of the hotshot's rocky career - ruined by boozing and womanising - with panache and ferocious charisma.

Earlier in the day on the same stage, Janet Street-Porter - Editor at Large of this newspaper - tells her life story in All The Rage!. This is not so much a confessional stand-up routine as a big mouthy rant - as she herself readily acknowledges. Street-Porter is also here, one gleans, to try out material she's working into an autobiography, and to ask her public what she should do next. After quitting her full-time post as Editor of the Independent On Sunday, apparently the job offers landing on her doormat have been laughably cruddy. She regales us with one anecdote about a fly-on-the-wall documentary which suggested she might like to undergo a sex change. What's likeable about this rough and ready show is the upfront gusto with which Street-Porter not only slaps herself on the back but also laughs at herself, appearing in hiking boots and an evening frock.

What's most personally revealing, however, is her recklessly frank mouthing off about her parents. Her mother sounds truly frightful. On one occasion, she apparently forced her injured daughter to go to hospital on the bus with her head under a tea towel. And on her deathbed, with both offspring present, she remarked that at least she had given birth to one success. Ouch.

k.bassett@independent.co.uk

'Dark Earth'/ 'The Straits'/ 'The People Next Door': Traverse (0131 228 1404) to 23 Aug; 'Islands in The Stream': St Stephen's (0131 558 3853), to 24 Aug; 'Hurricane'/ 'All The Rage': Assembly Rooms (0131 226 2428), to 24 August