I don't know how to describe five million starving kids any more. I'm sick of it myself

Nearly two decades ago, famine in Ethiopia stirred Bob Geldof to organise the Live Aid concerts. Yesterday he was back in Addis Ababa, warning with characteristic bluntness that mass starvation would return to this part of Africa unless the rest of the world did something.

A lot has changed since the 1985 concerts, which turned a foul-mouthed Irish punk rock singer into an international icon on a par with Mother Teresa. These days the honorary knight is a television entrepreneur and Third World advocate who releases the occasional record. Many younger people might know him better for the breakup of his marriage to Paula Yates, and The Big Breakfast, the programme they launched together, than for his social activism.

In Ethiopia, meanwhile, the murderous dictatorship of Mengistu Haile Mariam, who worsened the famine by denying aid to his opponents, was overthrown in 1991. By that time the collapse of communism had stripped him of his Soviet bloc support.

But the Horn of Africa remains poor and vulnerable. Millions are under threat when the rains fail, as they have done for the past two years. With the international community slow to react to warnings of a renewed slide into starvation, "Saint Bob" has once again been summoned to help.

Arriving in Ethiopia yesterday on his first official trip for 18 years, Mr Geldof accused the European Union of failing to release enough food stocks to prevent a repetition of "the horror of the eighties", when nearly a million died. "The EU have been pathetic and appalling, and I thought we had dealt with that 20 years ago, when the electorates of our countries said never again," he said after meeting Meles Zenawi, the Prime Minister, for an hour at the start of his five-day visit.

Today, some 12.6 million people, about one in five Ethiopians, face severe hunger or starvation as drought blights some of the country's most productive agricultural regions. The cost of emergency food aid is estimated at nearly £500m. The United Nations says Ethiopia needs 1.5 million tonnes of food aid this year, but Simon Mechale of the country's Disaster Prevention and Preparedness Programme told international donors at the end of April that there was a 340,000-tonne shortfall in the amount needed to prevent widespread starvation.

All the invective the former Boomtown Rats frontman can command will be needed to draw attention to the plight of Ethiopia at a time when the Western world is preoccupied with the threat of terrorism and the aftermath of recent wars in Iraq and Afghanistan. The country forfeited much sympathy when it fought a bloody border war with Eritrea between May 1998 and December 2000, which squandered thousands of lives and cost both sides $1m (£609,000) a day.

Mr Geldof said the timing of his mission was also intended as a "wake up call" to this weekend's G8 summit of world leaders in Evian, France. The US wants fellow members of the rich countries' club to contribute to the rebuilding of Iraq, but the singer demanded that they also help Ethiopia. "The G8 must move to reach substantial areas of need, like in Africa and particularly in this country which is ... trying to move forward," he said.

Ethiopia is trying to help itself. On Sunday about 20,000 people attended a Live Aid-style concert in Addis Ababa's Meskel Square, sponsored by a home-grown campaign called "A Birr for a Compatriot", which hopes to raise one birr (about 6p) from every Ethiopian to fight the effects of the drought. But as outspoken as ever, Mr Geldof did not spare his hosts either, calling on them to face up to another problem - the Aids crisis that affects 6 to 10 per cent of the country's 65.5 million population.

"Compound that with the drought and the near famine conditions - why are you not talking about this and coming up with the solution? You will see a societal collapse due to this unless you talk about it and demand that your politicians talk about it," he said after meeting 10-year-old Meseret Tadesse, who is HIV positive and whose parents died of Aids.