MUSIC / Fever pitch: Stephen Johnson on an evening of little-known Handel

Twenty years ago the idea of spending an evening listening to little-known Handel played on 18th-century instruments would probably have been as welcome to the average London classical concert-goer as a weekend of country and western. And while today an opera like Alcina no longer counts as little-known, it was still an uplifting surprise to see St John's Smith Square packed to the gods for the Orchestra of the Age of the Enlightenment's programme of Handel arias and orchestral works.

What followed was more encouraging still. First came the overture to the opera Il pastor fido - an eventful multi-section work, more like a Baroque concerto for orchestra than the modern idea of an overture. As the programme note rightly pointed out, it is too good a work in its own right to be sunk by association with one of Handel's less arresting operas. Imaginative resourcefulness reached its height in the Adagio, a lovely oboe aria with a breathtakingly bizarre combination of bassoon and double bass at its heart.

The playing here, and in the two Concerti a due cori (Nos 2 and 3), was of a high order. Those who have got to know the period instrument sound from well-edited commercial recordings may have found the occasional lapses in intonation or tonal polish disturbing, but to those who know how temperamental gut strings or 'natural' horns can be, the technical quality should have been apparent throughout. The horn playing in particular was remarkable - hardly a split note to be heard in the Second Concerto, and plenty of zest and panache.

No doubt the main draw was counter-tenor James Bowman. Not long ago there were expressions of concern about Bowman's technique, but if the seven arias in this programme were anything to go by, his current form is impressive. Yes, there were a few weak moments at the extremes of range in the virtuoso La bocca vaga ('Her pretty mouth') from Alcina, but the expressiveness and sense of larger shape were the kinds of bonus for which one overlooks minor impurities.

This feeling for an aria as a single phrase was perhaps the finest feature of Bowman's singing. Watching him, some may have found the hand movements and facial expressions mannered, but it seems that by these very gestures he is able to get such musical results - a form of self-conducting, perhaps. In the final billed item, the achingly beautiful Verdi prati ('Green meadows'), also from Alcina, that musicality reached its peak. Bowman's feeling for the long line doesn't preclude attention to tiny, heart-stopping turns of phrase - far from it; it would be hard to imagine anything less like the continuous romantic legato, the target of so much spleen in the early days of period style-consciousness.

Though advertised as such, Verdi prati wasn't quite Bowman's finale. As an encore he offered Fammi combatteri ('Bid me combat') from Orlando - a brilliant piece, brilliantly sung and played. There were one or two hints of tiredness in the winds in the concluding item, the third Concerto a due cori, but there was enough Handelian energy and rhythmic vitality to set the spirits singing. Perhaps Handel should be available on prescription.