It’s mid-October, and at Harvey Nichols Fifth Floor in Knightsbridge, Damien Hirst, Kim Cattrall, Thandie Newton, Dinos Chapman and Jefferson Hack have gathered to sip champagne and nibble tortellini with pea and truffle foam. Twenty yards away, through the giddy band of glittering, urbane partygoers, a boy with Russell Brand hair and tight trousers is throwing a curvy girl in a strapless dress around the dancefloor.

Presiding over the bash are Bono and his wife, Ali Hewson — and for once, it’s not his gig. It’s nearly 18 months since Hewson launched the ethical clothing line Edun, in partnership with the high-end jeans label Rogan. Since then, the brand has designed and manufactured 120,000 pieces of clothing, as well as printing 100,000 Edun Live T-shirts for merchandising use by various bands. This latest event is to mark the release of 20,000 T-shirts to tie in with the One campaign to combat Aids and poverty in Africa: of the £28 price tag, £7 goes to Alafa, a Lesotho-based Aids charity.

The scene illustrates how far the ethical movement has come. Conscious consumerism is Edun’s sole raison d’être. Any third world — the couple are still having to inject their own money into the company. But getting this ambitious project off the ground was never going to be easy, and the potential benefits are huge.

What’s clear is that Hewson’s commitment is total. I first met her early last year on a huge country estate outside Dublin owned by the Guinness family. She, Bono and Gregory were launching Edun with a photoshoot for a big fashion glossy. We sat around the fire for much of the afternoon, with Bono holding court. But he repeatedly deferred to his wife and her vision for Edun. “I’m definitely the least important leg on this table,” he said. “I’m there to keep telling them what a great table they’re making.”

A couple of months later, I accompanied Hewson on a visit to Edun’s factory in Lesotho, a small mountain kingdom in southern Africa devastated not only by the Aids epidemic but also by a defunct garment industry. She reeled off statistics and explained the mechanisms of international trade agreements and tariffs with practised ease. After Africa, she was flying straight to New York for an Edun launch during fashion week — which friends ranging from Salman Rushdie and Christy Turlington would attend — then on to Los Angeles to sort out a house for the family to live in during the opening months of U2’s Vertigo tour. It was a mad whirl of overlapping personal and professional commitments.

Back home, she has four children to organise — the school run in the morning is madness. It can’t be easy when your husband keeps disappearing off on world tours that last two years and you’ve got a growing international fashion brand to take care of.

None of it seems to faze her, though. “I’ve resigned myself to the guilt you feel when you drop your child off every morning,” she says. In any case, her attitude is that, from early on, she knew her celebrity capital could pay dividends. In Ireland, she is well known for other hands-on campaigning work involving Sellafield radioactivity in the Irish Sea and Chernobyl fallout in Belarus. “I was given the opportunity to use some of that (fame). I was reluctant, because I don’t see myself as a celebrity in any sense. But sometimes you feel you’ve been given an opportunity to do something and it’s only cowardice that stops you doing it.”

So when U2’s Vertigo tour finally ends in Hawaii next month, will it be easier to get more done, or does Bono get in the way when he’s at home? “No, he’s actually great at doing the school run. But it would be helpful if he could come home. You don’t like to have both parents out of the country at the same time — neither of us likes to do that at all. But you know, it isn’t always possible.” Hewson smiles. You just know she’s got it covered.

One T-shirt, by Edun, from Harvey Nichols; 020 7235 5000, or online from www.edun.ie

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