THE Benjamin Britten centenary year is now upon us. Celebrations are being mounted across the country, and indeed abroad, throughout 2013, reaching a climax in the composer's 100th birthday on St Cecilia's Day, 22 November.

Highlights of the year include a daring performance of his opera Peter Grimes on the beach at Aldeburgh, where the tragic events of George Crabbe's poem, on which the opera is based, unfold.

"A Boy was Born" is a Britten series running under the auspices of the City of Birmingham Symphony Orchestra, Symphony Hall, Birmingham, and its affiliates, and includes events at the Birmingham Town Hall, once the haunt of Mendelssohn and Elgar.

Fittingly, it was Ex Cathedra who introduced the celebration with a concert devoted entirely to Britten. This Midlands-based choir, founded and conducted by Jeffrey Skidmore, is now among the top-ranked executants of sacred choral music: notably the works of Delalande, Charpentier, composers of the South American Baroque, and, most recently, Giovanni Gabrieli (whose uplifting and ravishing Sacred Symphonies feature on their newest disc, Hyperion CDA 67957).

What a concert, and what quality! First came Britten's famously buoyant setting of the Jubilate Deo, performed with freshness and finesse quite distinct from when the work is sung by young voices. A Hymn to the Virgin, with its extraordinary echo effects (in Latin) sung by a four-voice semichorus, to which the secure lower voices (Stephen Davis, Nick Ashby) gave strength to the two melting upper lines, was not just touching: it was sensational in its beauty and concision.

In tuning, rhythmic subtlety, responsiveness to the conductor's lead, blend, and the quality of individual voices, Ex Cathedra, like Harry Christophers' The Sixteen, is now world-class.

The structure of A Boy was Born, the title work, is a fraction bumpy. Encouraged in his teens by his mentor Frank Bridge, Britten was not yet 20 when he pieced together the sequence of rare, exquisite, and very early carols, interspersed with interludes of finesse and imagination. Britten's structures - Our Hunting Fathers, Les Illuminations, even the War Requiem - have a habit of proving themselves with time. Whether in fashion or out, he had the unerring rightness of genius.

The Coronation was a church as well as a state occasion. Britten's choruses from Gloriana (he called them "Choral Dances", and they do indeed dance, especially in Ex Cathedra's scintillating reading) are among the most uplifting tributes to an English monarch since Handel turned out his Water Music.

Time, Concord, the salutation of Norwich and its aldermen to a former Elizabeth - the librettist William Plomer's poetic sentiments could be pure Tudor. The sublime, the syncopated, the scherzoid, the serene - all these moods were encapsulated, with special credit due to the upper voices.

Auden's Hymn to St Cecilia - "In a garden shady this holy lady . . .", with blonde, naked Aphrodite in hot pursuit - benefited from some lovely solo singing. The soprano at "O dear white children . . ." ("O weep, child, weep, O weep away the stain") was marvellous; and the alto, Martha McLorinan, furnished some of the most characterful individual touches of the evening.

It was another alto, Matthew Venner, who might have supplied the climax of Rejoice in the Lamb, Britten's tribute to the unhinged poet Christopher Smart, who was not unlike Blake in his innocent visions. This piece was written for Canon Walter Hussey at St Matthew's, Northampton. Here the only error of presentation occurred: Venner sang from the organ gallery - a nice conceit - but his exquisitely expressive quality was seriously diminished. For all this brave mouse's personal valour, he was rendered, unfortunately, an ineffectual squeak.

The enunciation by the soprano Amy Wood, contemplating her cat - faithful, godly, and surpassing in beauty - was utterly perfect. Laurels also went to the tenor, Ashley Turnell, who, hymning the flora ("For the flowers are peculiarly the poetry of Christ"), furnished the most wonderful singing of the whole concert. The choir, and some of Ex Cathedra's younger singers, too, sounded the best I have heard them. Lucky Birmingham. Lucky music.