Anyone in Scotland asking “What has the National Theatre ever done for us?”

was likely to have had a robust answer from the hundreds of young people milling around Edinburgh’s Royal Lyceum for the Scottish showcase of Shell Connections 2003.

Connections was established more than 10 years ago in response to demand for new material for young people to perform. In each cycle of the programme, the National Theatre commissions new plays from at least 10 playwrights (this year eight from Britain and one each from Norway and Finland) and offers them to schools and youth theatres - this year 165 - across the UK (and increasingly abroad). Each company is free to choose which one to perform as a premi re on their own patch.

Somewhere in their supportive audiences of friends and parents is the lonely figure of an assessor appointed by the National Theatre, monitoring the productions for selection to the national showcase in mid-July on the South Bank, London.

How the productions are chosen is known only to the National Theatre. There are no published criteria for assessment and, although the assessor will talk to the company after their performance, nothing is put in writing.

Instead, Connections works by that best of all governments, benevolent despotism. The end result is a showcase of the better (if not the best) productions of each of the commissioned plays which also represents each of the regions.

The National Theatre has carved the theatrical map of Britain into 13 regions, each with its own designated flagship theatre, which in May and June hosts a festival of all the plays chosen by its associated youth theatres. It was the turn of the Royal Lyceum to host all the Scottish companies this year and, though the Connections flag is traditionally moved annually from theatre to theatre, the Royal Lyceum makes no secret of its wish to become the permanent Scottish base for the programme.

That is why Steven Small, co-ordinator of the Scottish showcase this year, was careful to play his strong hand well. Among his best cards, of course, was the theatre itself and its location. He was aware that the sponsors and the NT picked up on the Royal Lyceum’s claim to reach a wider public. He emphasised, too, the way the young people “get a real excitement from working in the Lyceum and simply being in a theatre like this”, gesturing at the plush velvet and ornate paint and plasterwork of the auditorium. It was a point underlined later when a member of the Dundee Rep Youth Theatre group photographed it.

For the youth theatre members, the showcase was a giddy week of morning shopping on Prince’s Street, afternoon workshops of voice exercises, stage fighting, directing, Shakespeare and forum theatre and twice-nightly performances. The workshops were led by Royal Lyceum staff and youth theatre leaders, including Mary McCluskey, director of Scottish Youth Theatre, and John Haswell, director of Shetland Youth Theatre.

Shetland’s production of Lucinda Coxon’s The Ice Palace was chosen to open the showcase. The play (which was also chosen by Gordonstoun Youth Theatre) is based on a Norwegian short story about a dangerous winter journey taken by two girls.

Multiplex, by Christopher William Hill, writer-in-residence at the Plymouth Theatre Royal, was chosen by both Dunfermline Youth Theatre and the Commotion Youth Theatre of North Ayrshire. In this elegy to late 20th-century cinema, the cast play ushers and usherettes of a multiplex, coarse-tongued and slightly-deranged inhabitants of a ghetto of make-believe, illusion and disillusion. Into this shadowland, ruled over by the bully film-buff and would-be film-maker King (played with good presence by Dean Robinson in Commotion’s production) comes the Mouse (Mark Thomson) that will roar.

Commotion Youth Theatre, directed by Frank Smith, had their work cut out to create the weird underworld in the vastness of the Royal Lyceum and were not helped by the overly-simple mechanics of the plot and dialogue. Spike (Steven Murray) seemed to get most of the lines and, in a society that we were twice told is made up of plankton (the lowest form of life), the cool and the buffs (the top class), he was, by a long chalk, cool.

Aberdeen and Aberdeenshire Youth Theatre had chosen Finnish playwright Laura Ruohonen’s An Island Far From Here, translated by David Hackston. For two sisters, the idea of an island represents escape, a flight from all the rigmarole and folly of love which they can see infecting their girl friends. There is comedy in the paradoxes of those teenagers who want to injure their idol so that they can visit him in hospital and make his gratitude a step to love.

In contrast with this puppy-love, the sisters discover a woman living in a cellar, hiding from her son. He is returning from prison with poisonous feelings, not to mention a couple of sinister accomplices.

The play is a simple, believable and potentially difficult cocktail of youthful fantasy and realism, which directors Chris Lee and Louisa Brown and the company of 10 pull off with style and confidence.

Dundee Rep Community Company’s youth theatre chose Totally Over You by Mark Ravenhill, the playwright who sprang to prominence with Shopping and Fucking. The scenario might make up an episode of some children’s comedy.

Four S3 girls play truant from drama class to plan becoming celebrities by dating celebrities. To do this they have to dump their S3 boyfriends who, wounded and deprived, plan revenge. They adopt the simple expedient of posing as the ultimate boy band, with the rest of the drama class posing as assistants, members of the press, agents and fans, to convince the errant girlfriends that they are celebrities. A disco-style performance of their alleged first single, “So Totally Over You”, does the trick.

It is simple, mindless stuff but Dundee Rep Youth Theatre does well to put 21 actors on stage and the eight principals give bright and attractive performances.

Top of the bill was, inevitably, the Royal Lyceum Youth Theatre who, to the pleasure and embarrassment of the hosts, has been selected to perform at the national showcase in London next week.

The company chose Purple, written by the highly successful Norwegian Jon Fosse and translated by David Harrower, the same pair who were responsible for The Girl on the Sofa at the Royal Lyceum in last year’s Edinburgh International Festival. The play is the story of the break-up of an incompetent rock band, told in the stage language of Harold Pinter, with graceful gestures towards Waiting for Godot.

In a cold, dank cellar under a disused factory, the rock band tries and tries again, failing to improve. The melody guitarist, like Hamlet, believes his mother is a slut and revenges himself on his Ophelia, who may or not be the band’s groupie. The drummer, apparently driven by a jealous love for Ophelia, indulges in Birthday Party violence on the guitarist.

Once this superstructure of reference and allusion has started to impose itself on the story, acting becomes difficult. Before that, in the opening scene between the Girl (Linzi Campbell) and the Boy (Ben Clifford), living is easy, the relationship is held and the silences are eloquent. The irruption of the psychopathic drummer (Michael Argyle) raises the tension but diminishes the dramatic possibilities and by the time the bass guitarist (Ellis Thornton) and the singer (Steven Croall) arrive for the band’s rehearsal, there is little they can do to balance the situation.

Nevertheless, the company turn in a taut, comprehensible performance that gripped the audience in hushed concentration. The reaction was very unlike that on their recent trip to the author’s homeland, where the audience laughed almost uproariously all the way through. Maybe we have no sense of humour. It is a courageous and rock solid production by Colin Bradie that will do no one’s reputation any harm when it is seen at the Cottesloe Theatre on the South Bank on Wednesday.

Shell Connections national showcase, July 15-22, National Theatre, tel 020 7452 3000

The Connections 2004 cycle has already started. For details, www.shellconnections.org