Brief Encounter, National Opera Studio, London<br/>Lufthansa Festival of Baroque Music, Various venues, London<br/> Academy of Ancient Music/Egarr, St John's Smith Square, London

Only the best baroque will do

It's a brave composer who'll suggest a Bach Partita as the warm-up act for their work, but Peter Wiegold did just that at the premiere of his 20 minute operatic adaptation of Brief Encounter: commissioned for the National Opera Studio at their attractive new premises in Wandsworth. Braver still, though, is setting a script so well-known that absent lines such as "There go my Banburys all over the floor!" are as loud in the imagination as those left in Dominic Power's libretto.

Like David Lean's film, the opera starts as Laura (Cora Burggraaf) and Alec (James McOran-Campbell) attempt to close their unconsummated affair with dignity and grace, only to be interrupted by silly Dolly Messiter (Lise Christensen): the clearest individual characterisation in Wiegold's score. Wiegold has an impressive sensitivity to atmosphere and a deft hand with periodicity: the commotion of the railway station is beautifully painted, as is the airlessness of Laura's marriage to "poor, dear Fred" (Paul Carey Jones) - in a highly-effective scene where Laura's fresh, bright soprano tessitura assumes a maudlin mezzo range to match Fred's cloying bass-baritone - and the unwelcome air of corruption that lingers like stale smoke over her assignation with Alec in a borrowed flat. But the invention and subtlety of the orchestral score - played here by the Southbank Sinfonia - far outclasses Wiegold's homogenous vocal writing. With little to identify them, Laura becomes a neurotic and Alec a Lothario, while the crucial social divide between the middle-class lovers and the staff at the station café (Lorina Gore and Vassilis Kostopoulos) disappears.

At this point it's worth bearing in mind that NOS commissions are customised to their current intake of post-graduate students. Thus Wiegold's score has three keyboard parts for the trainee repetiteurs (Helen Collyer, Oliver Gooch, Michael John White) and a "chorus" of two fellow diners (Lee Bisset and Margaret Rapacioli) to comment on the action. The first device works well, adding propulsion to the score. The second device is dramaturgically misconceived. Why add characters? Why not use the Kardomah Piano Trio for comic relief? Regrettable too is Laura's frequent refrain "Nothing lasts forever!" as there are times during Brief Encounter when it rather feels as though the reverse is true. When Wiegold revises his score, I hope Noël Coward's light, brittle irony will be restored. The "Hop it!" confrontation is superbly handled, and the summery bliss of Laura and Alec's most intimate afternoon would benefit from more space. But Power's libretto needs serious reassessment. It could be brilliant. It could be touching. As it stands, Brief Encounter is definitely worth seeing - for the uniformly excellent singing of this year's NOS students and the excitement of seeing what can and cannot be done with such iconic material - but a fascinating failure.

Twenty years ago, when the Lufthansa Festival of Baroque Music was founded, period instruments were a rarity. Today, they can be heard at any major venue. Ensembles such as Les Musiciens du Louvre, Les Arts Florissants, the Amsterdam Baroque Orchestra and the English Baroque Soloists routinely play to capacity audiences, while at Glyndebourne the Orchestra of the Age of Enlightenment play anything from Handel to Weber opera. Does mainstream assimilation spell the end for specialist festivals? Audiences no longer want just any old Baroque. They want the very best. Let us draw a veil of discreet silence over Ensemble Européen William Byrd's under-powered opening concert at St John's Smith Square then - suffice to say that Britain does not hold the monopoly on uncharismatic performances of Charpentier's histoires sacrées - and move instead to Lufthansa Artist-in-Residence Paul Agnew's superb recital of petits motets with harpsichordist Béatrice Martin and gamba player Anne-Marie Lasla at the Wallace Collection.

Among tenors of his generation, Agnew is now the pre-eminent exponent of French Baroque. Its agréments have found an ideal medium in his mellow, liquid voice, and that elusive marriage of nature and artifice that is intrinsic to the music of Gilles, Campra, Couperin and Clérambault is perfectly balanced in his singing. From the declamatory drama of Clérambault's Abraham to the deferential psalmody of Couperin's Usquequo Domine, this was one of the most assured vocal recitals I've attended: secure, warm, intimate, continually involving and accompanied with absolute expertise. Agnew has grown into his sound with ease, Martin's solo and continuo playing was exquisite, Lasla's intense account of Marin Marais's G major Prélude and Chaconne from the second book of Pièces de violes quite breathtaking. Should the remainder of the Lufthansa Festival match this standard, it will more than justify its niche.

Back at St John's - though not under the Lufthansa aegis - the Academy of Ancient Music concluded their 2003/4 season with a programme of Bach Concertos directed from the harpsichord by Richard Egarr. Anyone expecting glittery, rigid perfection in either the D minor or G minor Concertos (BWV 1052 and 1058), the B minor Orchestral Suite or the Fifth Brandenburg Concerto will have been caught out by this austerely populated, rhythmically inventive performance: an event where AAM's eight virtuosi located an improvisatory groove that transformed this familiar repertoire into a dazzling, vital, percussive and perpetually surprising exchange of changing textures and ideas, despite the string-slackening humidity of a rainy June evening. With exceptional contributions from Egarr, flautist Rachel Brown and violinist Pavlo Beznosiuk, this was lively, discursive, idiosyncratic, fluid, exciting, risky, funny, characterful and original. Exactly what one wants in Bach and what one so seldom gets.

a.picard@independent.co.uk

'Brief Encounter': National Opera Studio, London SW18 (020 8874 8811), 3pm and 4.30pm today