The sound of women doing laundry filters through the front door and electricity is intermittent. A cat chases a rat across the corrugated-iron roof, ruining another vocal take. Just another day in the studio in Addis Ababa, August 2006. Tsedenia Gebremarkos prepares to try again.

It wasn’t always this way. In the late 1960s, Ethiopia was home to some of the funkiest big bands on the continent, long before the country was pegged as a drought-stricken hell by Band Aid. Forty years on, a concert at the Barbican in London on June 27 brings together for the first time the era’s greatest stars: the singers Mahmoud Ahmed and Alè-mayèhu Eshèté, the saxophonist Gétatchèw Mèkurya and pianist Mulatu Astatqé. Musically and emotionally, it promises to be among the gigs of the year. The following night they headline at Glastonbury, an inspired alternative to Jay-Z.

“It’s beautiful,” says Astatqé of the reunion. “I think I’ve played with each of them in the past, but not in at least 20 years. You put it all together, all those different types of music . . . Beautiful.”

The way he whispers his favourite adjective betrays his background on the London jazz scene of the 1960s. There is still a trace of modernist cool about the dapper man I meet in a restaurant bar, and it is easy to picture him in his twenties, hanging out in the Metro Club on Tottenham Court Road with his friends Ronnie Scott, Joe Harriott and Tubby Hayes, the tenor sax player who encouraged him to play vibes. That is, when he wasn’t on the stands at Arsenal, cheering on the team he still follows.

Astatqé later moved to the US to study at Berklee College of Music in Boston and live the Johnny Staccato life in New York. “At the time, the three corners of Africa were all there,” he recalls, referring to Fela Kuti from Nigeria, and the South African “Hughie” Masekela. In 1966, in cahoots with a group of like-minded souls, he recorded two LPs called Afro-Latin Soul, the first “Ethiojazz” albums.

Currently a fellow at Harvard University, where he discusses Charlie Parker with mathematicians and Miles Davis with geneticists, Astatqé enjoys explaining Ethiopian musical theory. There are three legs of Ethiopian pop, he tells me: traditional folk culture and the music of the Azmari minstrels; the Coptic church, which split from the rest of the Christian world in the 5th century; and Haile Selassie’s love of brass bands.

Country, gospel and horns: these, unsurprisingly, are the same ingredients that shaped American soul and Jamaican reggae. Using a pentatonic scale, the Ethiopian groove sounds familiar but strange, as if holding up a cracked mirror to Otis Redding or Aretha Franklin. “The same universal notes connect us all,” Astatqé smiles. “We had them centuries ago, but the genius of the European composers was to spread them round the world.”

When he returned home in 1968, he found Ethiopia enjoying a pop explosion. A mood of freedom had swept through the country in the 1960s, enabling the growth of independent record labels which used moonlighting musicians from the brass bands. Selassie had invited Armenian horn players to his country in 1924, and encouraged the formation of orchestras under the auspices of the police, Army and imperial bodyguards. But despite the emperor’s patronage, music was still the occupation of disreputable troubadours: Eshèté, known as the “Abyssinian Elvis” or “Ethiopian James Brown” at different stages in his career, will never forget his shamed, gun-wielding father chasing him through a nightclub.

For almost a decade, Addis was every bit as swinging as London, but a hardline Marxist Government seized power in 1974. The Derg, lead by General Mengistu Haile Mariam, imprisoned Selassie and his followers and enthusiastically waged civil and international wars while leading their country into chaos. The lights went out on Africa’s most exciting nightlife. “They objected to the Western music that we were playing,” Astatqé says. “They didn’t come out and say it, but we knew.” To survive, he composed soundtracks for political plays and recorded cassettes of folk music for Ethiopian Airlines’ in-flight radio. Others were less fortunate, forced out of music in order to make a living as the economy collapsed. Eshèté simply refers to the period as “hell”.

Although the Derg lost power in 1987, the shattered country remained in darkness for years afterwards. Even today, life for a young musician is tough, as I learn when talking to Samuel Yerga, the 21-year-old keyboard prodigy with Dub Colossus, the band whose recording sessions were interrupted by the cat and rat. They will also be playing the Barbican and Glastonbury shows, though they travel light.

“I didn’t have a piano until this spring,” he says, “but most musicians don’t own their instruments, we just can’t afford them. There are so many other problems for the Government to fix first that music is still not an accepted part of the culture again. After the Derg, we are the first wave to break the ice, to take traditional music and turn it around. It will be good to see how people react.” He shouldn’t have too much to worry about, Ethiopian music has never had quite as much cachet beyond the country's boundaries.

The mainstream revival of interest sprung from the efforts of Francis Falceto, a French music promoter. He heard a track by Mahmoud Ahmed, travelled to Addis and found the singer working in a shop. A man possessed, Falceto hunted out the musicians and producers responsible, bought all the original vinyl he could find, and convinced a record label to release a compilation of the best. Nothing shoddy or opportunistic: the musicians had to be given the platform they deserved. The Éthiopiques series, which now numbers 23 volumes plus a Very Best Of endorsed by everybody from Elvis Costello and Robert Plant to Arcade Fire, was one of the cult hits of last year, and the live dates look like taking Astatqé et al to a whole different level of fame. He may have seen it all before, but the second bite will still be special.

“I want to take this moment and build on it,” he says, clearly relishing the opportunity. “I want to rediscover what was lost. That would be beautiful. Beautiful.”

Éthiopiques, Barbican, London EC2 (www.barbican.org.uk 020-7638 8891), Jun 27 2008 (returns only)

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