The U2 singer arrives today in Nigeria, Africa's most populous nation, having already visited Lesotho, Rwanda and Tanzania to highlight the benefits of his Product RED campaign. But the tour was almost aborted before it began.

Fresh from his day in the editor's chair at the London Independent on Monday, Bono flew to Johannesburg, but he was initially barred from entering South Africa. The reason: so extensively has he been travelling the world to whip up support for debt relief, increased aid and fairer trade terms for Africa, he didn't have a blank page left in his passport. A quick call to Nelson Mandela solved the problem, and the rock star and his entourage were waved through.

In Lesotho . . . the tiny, mountainous kingdom surrounded by South Africa . . . Bono and his wife, Ali Hewson, visited a textiles factory that was almost forced to close after an agreement which had protected textile industries in developing countries ended last year. The factory, the only major employer in the remote town of ButhaButhe, was saved after an order from Mrs Hewson for a range of T-shirts to be sold at U2 concerts.

Nakadi Jabbie, the owner of the factory, said the order was better than aid. "When people work, and they can buy their own food and take themselves to the clinics, then it means they are doing it themselves and they are not just receiving food parcels."

Lesotho has one of the highest HIV/Aids infection rates in the world. Unlike its neighbour, South Africa, the Lesotho government has encouraged its citizens to take an HIV test. The prime minister, Bethuel Pakalitha Mosisili, has even subjected himself to a test.

Bono said it was "scandalous" that Lesotho had not benefited from debt cancellation under a global scheme managed by the World Bank and IMF to write off the debts of the world's poor countries.

"The reason Lesotho has not received debt cancellation is because it has been disciplined, it has been punished for the fact that it has been a good borrower in the past and has paid back its debts, so we want to address that, " he said.

In Rwanda's capital, Kigali, he promised to keep up pressure on the US and other wealthy nations to make good on their promises of increased aid for Africa, saying there were signs the G8 industrial countries were back-tracking on last year's promises to double aid to Africa by 2010 to $50bn.

The G8 is scheduled to meet in Russia in July, and Bono, presumably with new passport in hand, is almost certain to be there.