Elvis Costello & Steve Nieve, Royal Festival Hall, London

Growing up, but all too gracefully

Too often, rock stars aren't as good as they used to be because they're too old. Elvis Costello's problem is different: age hasn't harmed his singing ability, and it's only enhanced his cerebral, bespectacled image. Elvis Costello isn't as good as he used to be because he's too grown up.

Costello has always been a plunderer of musical genres, but while you felt that he made the country album Almost Blue (1981) just because he wanted to, his recent work seems to be driven more by the hope that it would be interesting. His collaborations with Burt Bacharach (Painted From Memory, 1999) and the Brodsky quartet (The Juliet Letters, 1993) certainly are interesting and innovative. But they don't have the indefinable, fascinating urgency that made Costello's early records so brilliant. The later music is born more of intelligence than of inspiration.

Costello's new album, North, recalls Painted from Memory in that it is a collection of torch songs in stylistic and lyrical homage to his new lady, Diana Krall. It's very serious. Hence this pared-down concert at the South Bank's Mind Your Head festival, with Costelloaccom-panied only by Steve Nieve.

It is a relief, then, to see the man bound onstage and launch straight into "Accidents will Happen" from 1979's Armed Forces. There's even a distortion pedal on his acoustic guitar. Nieve, meanwhile, is captivating: looking like a mad professor, he treats the piano as though it's been giving him electric shocks. He gets to shine especially on the spooky "Shot with his own Gun".

The first track from North is the fifth number. Costello can't resist explaining what the song, "Someone Took the Words Away", is about: it's about how falling in love can be scary. The tone is perhaps a little didactic, but fair enough. The next four songs get the same treatment, and Elvis strikes an operatic pose as he sings.

Which brings us to the voice. It infuriates me when people say Bob Dylan can't sing, and I know some love Elvis Costello's voice just as much, so I say this with hesitation. It's clear that Costello has great technical skill and control as a singer, and he takes pride in it. Tonight, with "Look mum, no hands" glee, he does several songs off-mic. But the fact is, it's a whiny voice. Costello's real skills as a vocalist lie in spitting out rapid-fire rhymes or sneering through angry choruses. Rocking renditions of "Man out of Time" and "What's so Funny 'Bout Peace, Love and Understanding" demonstrate this tonight. The long vibratos that characterise North, meanwhile, are just not pretty. This seems like the work of an ambitious adult taking on a challenge.

"God's Comic" from 1989's Spike (an ironic choice, given the Mind Your Head festival's New Meanings in Sacred Music subtitle) comes as a welcome relief. It gets a long, spoken interlude: "This song proposes a view of the afterlife that is not entirely theologically correct." It's funny! At moments like these, the Costello and Nieve show becomes vaudeville entertainment, chiming well with the storytelling of the songs from North.

The Brodsky quartet appear and deliver a fantastic version of "Pills and Soap" from Punch the Clock (1983). For once, Costello's classical pop sounds as good live as it looks on paper. They then return to North, and Costello and Krall's affair gradually unfolds through the songs. But it goes on for too long. When he sings "Let Me Tell You about Her", with its line "When I start to sing they run for miles", I feel like doing the same. Yet that song's evocation of the desire to tell all explains the album. Costello appears genuinely, sincerely grateful to us for listening to the new songs. "It really means a lot to me," he admits.

So much so that he keeps leaving the stage, then returning. Suddenly he's not a boring grown-up, but an infuriating child, unable to resist doing just one more - and it becomes clear that North is in fact not another cold, experimental project for Costello, but an emotional attempt to capture a personal experience. It's touching to see such a well-established and successful performer so anxious to communicate with his audience. But in this self-consciously sophisticated genre, Costello's abilities don't suit his ambition.