IN TWO years' time at Hereford, the Three Choirs Festival will celebrate its (putative) tercentenary. In 2014, at Worcester, it will honour the First World War, with a commission from the Dresden-born composer Torsten Rasch.

The Festival was back in Gloucester this year. It may date back to the 18th century, but it is a model 21st-century event. Everything about the organisation is top-notch. Practical problems are mopped up rapidly. This year's most vexing was external noise that nearly wrecked the first song recital at the newly restored Blackfriars Priory.

Fortunately, the baritone Roderick Williams, a regular at the Three Choirs, with his ravishing command of English song delivered invariably from memory, seemed quite unfazed. His recital included Rasch's Songs, a foretaste of next year. You can hear how those composers Rasch has been likened to - Mahler, Schoenberg, Berg, and Webern - all play out in his informed style, which is infused with much else - even pop music.

He here sets words by the Second World War poet Alun Lewis, and Gloucester's own Ivor Gurney. The poems are evocative of war and a passage from darkness to light: coming last, Housman's two-stanza "Here dead we lie Because we did not choose To live and shame the land From which we sprung. Life, to be sure, Is nothing much to lose, But young men think it is, And we were young" surely says it all, for next year as well as any.

Half of the joy of the English Lied is the texts chosen for setting. Richard Sisson (b. 1957), for instance, included the last poem in a cycle full of Housman rarities: "Yonder see the morning blink", "They say my verse is sad: no wonder" - which ends: "This is for all ill-treated fellows, Unborn and unbegot, For them to read when they're in trouble And I am not."

William Blake was especially featured: Britten's Songs and Proverbs, weeping the hopelessless of the human condition; Nicholas Marshall's (b. 1942) tender and spare "The Garden of Love"; and the best item in the programme, Williams's own treatments of "The Angel" and "The Shepherd" - with late warm ninths redolent of Vaughan Williams - which drew on each part of Songs of Innocence and of Experience. Even the single Holst song, setting a moving dialogue, "What will they give me when journey's done?" by Humbert Wolfe (1885-1940), spoke reams. Not everyone understood why the word-sheets were issued afterwards; it was an annoyance.

Among the other recitals, I was struck by one given by the baritone Philip Lancaster, a world expert on Gurney's songs, who in "An Elizabethan Centenary" presented, at St Mary de Lode, English music with harp and a wind sextet. This was a polished young ensemble from the Welsh College of Music and Drama. The programme included Parry, Stanford, Finzi, and Gurney's friend Marion Scott - her Romance, here with clarinet and harp. Oboe, as the composer intended, would have been better.

The mezzo-soprano Susanna Spicer sang her part agreeably; but it is Lancaster's own voice that gave special pleasure. The harpist Megan Morris shone in Howells's Prelude No. 1; and Spicer in his melancholic song "King David", in which Lancaster's cleverly thoughtful instrumentation felt as silky as Ravel. Only the title cycle, Gurney's five Elizabethan Songs, seemed not quite to work: so effective was the instrumentation that it diverted from Shakespeare's and Fletcher's (though not Nashe's) words. Still, this was what Gurney intended.

Blackfriars behaved impeccably for the tenor Robert Murray's song recital. He performed beautifully the bulk of a programme plotted by Andrew Kennedy, who was indisposed; and the venue proved uplifting for that small a cappella group The Songmen.

This adroit vocal sextet seemed to have all the merits of the King's Singers without the froth (though the pointless and unfunny bass round-off to their tragic "Skye Boat Song" ran that risk). It was a mistake, to my mind, to programme Janequin's La Guerre - 16th-century military spoof par excellence - instead of his jauntier farmyard efforts, alongside Poulenc's "Margoton" and "Clic, clac".

The Estonian Urmas Sisask's (b. 1960) Heliseb Väljadel - a touching prayer - came close to a Baltic "My Way": utterly wonderful from a polished gem of a group. Guy Lewis's top line is the plum; the second countertenor and arranger Ben Sawyer is a joyous bonus.

Gloucester was all agog for the arrival of Vladimir Ashkenazy to conduct, in his idiosyncratic, understated way, the Philharmonia and the Festival Chorus in the first night's gala concert. Ashkenazy was indeed a catch, though I would still put my money on the locally residing conductor Martyn Brabbins (missing this year, although we did get the Gloucestershire pianist Peter Donohoe astounding us in Liszt's B-minor Sonata and Wagner); or the home-grown chorister Edward Gardner, who returned midweek to conduct Wagner and Verdi.

But the real gala winners were in other categories: composer and performer. As one who knows far better than I remarked, the Festival Chorus - superb two decades ago when I first attended - has grown better and better. Their stamina is more reliable. They are better prepared and musically more sophisticated. They can now mix dynamism with subtlety, and, where necessary, rein themselves in. They now effortlessly rival the big BBC or London orchestra choruses.

Elgar, Sibelius, and Rachmaninov were Ashkenazy's composers - his kind of repertoire. He turned Elgar's Straussian overture In the South into a massive, beautifully spaced narrative, just as Adrian Partington did later with the rarer Falstaff. And with Rachmaninov's Edgar Allan Poe-based The Bells - Sleigh, Wedding Alarum, Mourning - "molten-golden", "a liquid ditty", "a gush of euphony": delicious Whitman-anticipating gush - he alchemised the chorus itself to gold.

But it was Sibelius who stole the show: the soprano Helena Juntunen brought such wonderment to Luonnotar (the founding of the universe by the daughter of heaven, lamenting her solitude), a spare, striking vocal scena commissioned for the 1913 Three Choirs, which was an inspired choice by Partington and his committee. She was to be outshone by another Baltic soloist at the week's end, but her aching solo made one walk out of the cathedral on air.

A gripe: French, German, and Italian words were printed elsewhere in the programme; so why not Russian (transliterated) and Finnish here? Were these languages judged too difficult for the average Three Choirs punter? That would be nonsense. Nor can an economic defence apply: the Three Choirs is about excellence in all departments.

Much else sang out in the Gloucester nave, which is wonderful for sound (the side aisles are perhaps even better). Worcester's Peter Nardone served up a valiant attempt to make the case for Samuel Coleridge-Taylor's tripartite The Song of Hiawatha. I found Part I, Hiawatha's Wedding Feast, jingoistic rubbish; but The Death of Minnehaha was a different kettle of fish - far subtler; and, while Nardone's full conducting confidence has yet to be proven (he is a fine singer, who began his career as a boy soloist at Paisley Abbey), he and the orchestra worked wonders with Hiawatha's Departure, orchestrally superb.

There was Arvo Pärt - not, unfortunately, in person (he sent a message), but conducted by one of his and other Baltic composers' doughtiest exponents, Stephen Layton. Layton also daringly assayed Sibelius's Second Symphony, a treat in that acoustic, with which the Philharmonia's vast experience had no trouble.

On the Wednesday, the baritone David Stout boomed the great bass introduction to the choral finale of Beethoven's Ninth - never a particularly apt Three Choirs inclusion, I feel - under Geraint Bowen's direction. It was Bowen who imaginatively prefaced an afternoon concert by one of the festival's several youth choirs with Britten's rarely heard choral pearl Hymn to St Peter. Young soloists in Rejoice in the Lamb, the bass especially, did well.

Edward Gardner, a former Gloucester boy soloist (under John Sanders, ten years since whose death was marked by the performance of several works) brought more professionalism than character to Verdi's Four Sacred Pieces, which are difficult to pull off. But his Tannhäuser overture - brass superb after a hint of tentativeness - was stunning. A vocal revelation, Emma Bell, standing in for Sarah Connolly, made hairs tingle in the Wesendonck Lieder - another centenary tribute to Wagner.

Perhaps the tribute to end all Wagner tributes was Partington's prefacing of one of the finest performances of The Dream of Gerontius most of us will hear with the Prelude to Parsifal, a work whose impact on Elgar, from score, was clearly immense. This hearing suggested that the parallels in Gerontius's early bars were fewer, or more superficial, than one had hoped; and yet clearly the one gave birth to the other.

But why was Partington's Gerontius so overwhelming? True, he had what some might see as the UK's best orchestra, superbly led by Zsolt-Tihamér Visontay, now a Three Choirs fixture. True, he had an exquisite young Gerontius in Toby Spence, the full beauty of his tenor voice now restored after a debilitating illness; the lesser asset of the usually superb bass-baritone Matthew Rose, whose Priest and keeper of God's House both sounded underwhelming (more familiarity with the acoustic might have helped); and the Estonian mezzo-soprano Kai Rüütel, who was the most affecting Angel I have ever heard (even Janet Baker included).

But it was Partington's insight into expressive oratorio, with its searing text from Cardinal Newman, which was the miracle of this festival. I sensed here, in someone who is also chorus director to the BBC National Chorus of Wales, an ability to crawl inside a huge score and see it all. The intelligence, the detail, the subtlety of intricate timing, the intimate rubati, each impeccably prepared and conducted, were awesome. Had he a direct line to its maker?