You don't get to choose your birthday, otherwise I guess the Royal Ballet School would have opted for another time - any other time - to celebrate its 50th. What with its parent company in the artistic doldrums, moving house, planning next week's closing-down party and dashing round and round Hammersmith flyover trailing balloons in an ill-conceived publicity stunt, it was a rum week to be having a gala.

The school puts on a show at the Opera House every year, and to call Tuesday's offering a "golden jubilee gala" suggested something rather lavish, which it wasn't. Balletomanes go dewy-eyed over the magnificent themed galas the House used to put on in Ashton's day, but the current administration seems to have forgotten how to do them. This one followed the school's regular format of "traditional dances" - children performing quaint little jigs and hornpipes - and a one-act ballet written specially for the event, then trawled endlessly through snippits from the classics danced by grown-ups with a student corps. This made no nod to the school's history beyond pointing to the fact that starry principals once passed through its ranks. Far better to have taken one long chunk - the entire divertissement act from The Sleeping Beauty perhaps - and put the students properly through their paces.

As it was, the imaginative thrust of the evening fell entirely to David Bintley and his new setting of Roussel's neglected ballet score of 1913, Le Festin de l'araignee. The scenario - a spider's attempt to secure himself a meal - provides bags of opportunity for lively anthropomorphism which Bintley exploits with wit and taste. I loved the goose-stepping army of Gestapo ants and the trio of aviator wasps, wickedly tricked out in Ruari Murchison's designs. Intrusions of gory realism (a stage strewn with corpses, a predator guzzling at a body) keeps the ballet refreshingly free from prettiness.

The School fielded some impressive soloists but told us nothing about them. The American Jerry Douglas as the spider is clearly cut out for a big career. Squatting over his long, lean haunches, arms dangling louchely, he gave a spooky impression of having eight legs. Twitching press-ups and a quivering gape-legged walk were among other spidery movements brilliantly imagined for him by Bintley. A duet with a short-sighted Mayfly (Carol- Anne Millar) provided some nicely pointed comedy, followed by a stunning coup de theatre when the anti-hero is concussed by a giant discarded cigarette packet bearing the brand name "De Valois". Ouch.

The final item was a choreographed assembly of the entire school and staff which climaxed in a toast to the school's founder, the legendary Dame Ninette De Valois, who, now months from her 100th birthday, rose to her feet to acknowledge a very long ovation. But even this attempt at Gala grandeur fell to earth when, the evening clearly at an end, Dame Merle Parke, stranded on-stage alongside Princess Margaret and hoards of juniors in gym knickers, had to beg "may we have a curtain please?"

English National Ballet's small-scale touring programme (one of two doing the rounds concurrently) was not without mishap when I caught up with it in Dartford on Wednesday, but under Derek Deane, the company has developed such a sure popular touch that I do believe all the dancers could fall over backwards and have their audience beg for more. This second night mid-tour, with a bill of one-acters and pas de deux, made a telling comparison with the stiff affair at the Opera House. There was an edge to ENB's best dancing that came from the simple desire to entertain, urged on by an audience which was palpably thrilled. During Elisabeth Miegge's Black Swan solo they only just restrained themselves from counting her 32 fouettes out loud, before erupting into cheers.

Star dancer Greg Horsman has never looked more sexy and at ease than in the one-act ballet Encounters, created on him last year by ice-skating supremo Christopher Dean. Episodes from Dean's own life story are set to a heart tugging selection of Paul Simon songs in a fluid style that draws on a dizzying number of ice-rink spins and turns but also comes up with some fine balletic innovation. It's a more interesting ballet hybrid than the Broadway mish-mash dreamed up by the great Balanchine for Who Cares?, the piece that ended the bill. With its perky Gershwin songs and its frilly dolly frocks, it's fun if you happen to like it, a lapse of taste if you don't.

One thing however is certain: ENB is riding high. Having just played its Swan Lake to 47,000 at the Albert Hall, it has no shred of doubt who its audience is or where it's going next.

Royal Ballet School: Holland Park Theatre, W11 (0171 602 7856), 15-19 Jul. ENB: Hawth, Crawley (01293 553636), Tues & Wed.