The saddest song in the world

The morna singer Cesaria Evora brings her particular brand of passion to Britain

Cesaria Evora's triumphant UK tour has had to tack on a second concert at the Barbican, because the first sold out many weeks ago. The dumpy, boss-eyed mezzo, universally known as "the Barefoot Diva", is often compared with Bessie Smith and Billie Holiday, but what they really share ismusical incorruptibility. Evora's voice has no affectation, no implicit invitation to share her tragedy, no self-conscious art. Within its small baritone register, and its level dynamic, it's one of the cleanest, most unadorned voices on earth.

Cesaria Evora's triumphant UK tour has had to tack on a second concert at the Barbican, because the first sold out many weeks ago. The dumpy, boss-eyed mezzo, universally known as "the Barefoot Diva", is often compared with Bessie Smith and Billie Holiday, but what they really share ismusical incorruptibility. Evora's voice has no affectation, no implicit invitation to share her tragedy, no self-conscious art. Within its small baritone register, and its level dynamic, it's one of the cleanest, most unadorned voices on earth.

What exactly is morna, the musical form she has made her own? A Cape Verdean ballad, usually expressing nostalgia, which goes at a languid pace: a Lusophone answer to the American blues. It's often compared to Portuguese fado, but the two have little in common apart from their dark harmonies and use of the delicately expressive 12-stringed Portuguese guitar. Where fadistas belt out their laments in tightly structured bursts of feeling, the morna singer tends to meander. And nothing's more mournful than morna.

Evora on stage is anarchy incarnate. She ambles around barefoot, taking puffs on her fag and swigs at her glass; every so often, she'll turn her back on the audience to sit down and think. She sings whatever she feels like singing, and if something has already gone down well that evening, then that's an excellent reason to sing it again.

She's just as anarchic in interview. She was one of seven children, and life was hard. How did her career begin? "By accident. A boy was playing in a bar, and I began to sing. I went on singing professionally for 10 years." First in bars, then as the star of the local radio station."

But life got harder, because when the Portuguese Revolution ushered in Cape Verdean independence, it also effectively killed off the tourist trade on which her livelihood depended. "So I decided to rest for a while." Her official website describes this "rest" as a desperate, drunken 10-year binge, but now - boldly rewriting history - she presents it as God's sign that she should preserve her strength for the career that opened up when a group of Cape Verdean fans forced her back out on the road. She began to perform for her compatriots in Portugal and France, and then released the immortal album Miss Perfumado, which brought instant fame. The discs she's released over the last few years have ranged musically far and wide, but Voz d'Amor, the new record she's here to promote this week, represents a wonderful return to her roots. Here is that original sweet pain, delivered with those lazy vocal swoops and slides.

"I sing whatever I'm thinking about - love, memories, the story of my life. You can dance to morna, but it's better to sit and listen." And be utterly swept away.

Cesaria Evora: Bridgewater Hall, Manchester, tonight; Colston Hall, Bristol, tomorrow; Usher Hall, Edinburgh, Friday; Barbican, London EC2, Sat & Sun. 'Voz d'Amor' is on BMG France