London Symphony Orchestra/Davis, Barbican Hall, London<br></br>BBC Symphony Orchestra/ Runnicles, Barbican Hall, London<br></br>European Union Baroque Orchestra/Biondi, Banqueting House, London

Blame it on the Times Literary Supplement's post-9/11 re-examination of Milton if you like, but it seems unlikely that any opera house will be rushing to stage Saint-Saëns's Samson and Delilah in the near future. For all that the music – an opulent, high-camp explosion of souk-scents, oiled eunuchs and whirling djellabas – points to a Cecil B DeMille extravaganza, the plot is pure uzi-and-combats political allegory. Samson, as the TLS reminded us, was the first suicide terrorist.

How much cultural analysis went into Sir Colin Davis's three concert performances with the LSO this week is debatable, but for lovers of fine orchestral playing this was an almost absurdly exciting event – not least for Davis's assertive eschewing of the usual syrup in Delilah's duplicitous Mon Coeur. Barbican Hall conventions allowed Saint-Saëns's painstaking thematic development to be heard uninterrupted by applause, while the frenzied Bacchanale made Dagonism seem a quite appealing religion. For lovers of French song however, it was a different matter. In terms of presence, polyglot leads José Cura (Samson) and Marina Domashenko (Delilah) were satisfying enough, with Domashenko having the edge with her rich, steady vocal projection, but neither filled out the personae of action-hero and vamp. Cura gave his usual smash'n'grab performance and the French of both, which involved the confusion of poison with poisson, was frankly incroyable. Among a superior supporting cast, Robert Lloyd's sepulchral Old Hebrew and Juha Uusitalo's terrifying High Priest demonstrated that, when you get the vowels and consonants correctly placed, French can be the most powerful stage language. For that matter, the London Symphony Chorus also showed great style, keeping well on the beat and well in character(s). An unstageable experience perhaps, but a fascinating one.

The same venue was mysteriously under-populated for the first of San Francisco-based conductor Donald Runnicles's Wagner and Wagner-inspired programmes with the BBC Symphony Orchestra. Was this massed no-show a reaction against Runnicles's daring (to true bearers of the flame) division of Tristan und Isolde into three separate performances or an indication of the poor esteem in which the BBCSO are currently held? By way of a rebuke to those who felt that they might not be up to Tristan, the BBCSO played far, far better in Act I than I've heard them play for years; more cohesive, more distinctive, more expressive and infinitely more accurate. Furisthermore, they even looked engaged, which marks a serious elevation from their recent demeanour. But Tristan bore the marks of having been rehearsed to a level whereby it could really fly, which Debussy's symphonic fragments from Le martyre de St Sébastien – the first of three couplings with music inspired by Tristan – pointedly did not.

If Runnicles's Debussy was merely muzzy – back-lit beauty is not enough – his Wagner was spectacular. The slow gestational conducting style worked perfectly here, linking well-prepared details of mood and character into a brooding emotional crisis. Among the singers, John Treleaven's Tristan was goatish of sound but heroic of character, Marc Le Brocq's Young Sailor metallic, crisp and deliciously lyrical, Christine Brewer's Isolde sensational. Alone among sopranos of similar vocal heft, Brewer does more than belt. Her lines are exquisitely shaped, her phrasing cleverly defined, her text as imaginatively coloured as lieder. With such a balance of athleticism and grace, her Isolde is worth the ticket price alone. Indeed, my only criticism is that the orchestra were allowed to swallow Dagmar Pecková (Brangäne) whole, though Pecková's is hardly a small voice. Providing Runnicles applies the same focus that he achieved in the Wagner to the first halves of February's two concerts, this series should work. For Wagner-virgins, it's a gentle de-flowering, while those who only want to hear Tristan can always spend another twenty minutes in the bar and slip in at the interval. Which, in retrospect, is what I rather wish I'd done.

At Banqueting House, the European Union Baroque Orchestra reached the penultimate performance of their tour with violin supremo Fabio Biondi; one of three they will make with early music luminaries through the course of their year's work. Drawn from ten countries, this orchestra of graduate players is a uniquely successful example of enlightened professional apprenticeship. Were anyone to think that Vivaldi might sound more or less the same as Geminiani or Sammartini, EUBO are the band to alter that perception; lending distinct character to composers otherwise bracketed in one big Baroque lump. Scintillating is the only word for them – so alert, responsive and imaginative is their playing – and though each player could walk into a job with any of Europe's period instrument ensembles tomorrow, I'd hazard a bet that EUBO boasts some future superstars in the form of Kathrin Sutor (cello), Christine Sticher (double bass), Cvetanka Sozovska (harpsichord), and Peter Whelan (bassoon). Remember these names: they're the Biondis, Christies and Minkowskis of the next generation.

a.picard@independent.co.uk