King, Canterbury Cathedral, Cathedral <!-- none onestar twostar threestar fourstar fivestar -->

The murder of Thomas Becket is the most site-specific climax of a drama in English history. Canterbury Cathedral chose not to stage T S Eliot's leaden play or any other existing script, but to host a new opera performed by professional singers, its own choir and organist and - adding a distinctive twist - Kent schoolchildren.

Composer Stephen Barlow conducted, librettist and performance poet Philip Wells gave himself a kind of Everyman part to comment on the action along with the children. Not that action is the word. King is better taken not as opera but as a meditation on conflicting loyalties. Otherwise you have to say, too many words, not enough to do.

Becket was canonised, but Wells chose his title accurately. The driving force was Henry II's inability to exert his will over the archbishop, and the text dwelt on the two men's friendship and heart-searching that their political rift caused them. This prompted what amounted to two homoerotic love duets, which Philip Joll and Robert Burt handled with manliness and sensitivity. However, it relegated Queen Eleanor, for all Kate Ludner's eloquent singing, to a go-between and kept the main characters meditating well past the bounds of decency.

On a plain stage behind the small orchestra, Harry Silverstein directed with clarity and an intense focus on projecting inner turmoil. The murder happened offstage in a transept, as in reality, against the background of rediscovered music very likely to have been sung at the time. As sung here by the choir, it was unexpectedly catchy.

What made the longueurs endurable was Barlow's own music. Little known as a composer, he came up with a style that sounded French, not just in its echoes of Debussy but in its instrumental colour. It featured a soulful solo for flugelhorn, and elsewhere Indian and Western percussionists swapped beats.

The event had a real lift from the children belting out their own lines. "Can they be best friends again?" said one, and words of heart-stopping directness came again and again. Since King was commissioned by Creative Partnerships, which is supposed to steer its resources to hard-done-by schools, it's hard to see why the kids didn't get more prominence. For the rest, buried away in there is perhaps the core of a concise one-acter, but a ruthless editor needs to get working.