Ali Hewson attends the launch party for Edun T-shirts and T-dresses. Photo / Getty Images Expand

Ali Hewson attends the launch party for Edun T-shirts and T-dresses. Photo / Getty Images

For someone who runs her own fashion label, throws herself into promoting charitable causes, is married to the world's most prominent rock-star-turned-campaigner and has four children, Ali Hewson is very calm.

Bono once said there was, "something so still about her," and apart from her visible coyness about being photographed - she asks nervously if she looks OK because she hasn't seen a mirror - it's true. It must be this composure that has enabled her to stay grounded while globetrotting, multi-tasking and generally throwing the metaphorical juggling balls higher than most. Although the very pretty 48-year-old founder of the ethical fashion label Edun clearly

feels strongly about her latest charity T-shirt project, and the need for more thoughtful consumerism, there's no guilt-inducing alarmism or tub-thumping in her manner. Rather, Hewson's calm explanation of her philosophy, and of some of the horror and suffering she hopes to alleviate through her business, is all the more persuasive for being so serenely delivered.

We meet in the plush personal shopping suite at Selfridges before the launch party of Edun's new charity T-shirt collaboration with the magazine Dazed and Confused.

She solicitously offers me a glass of water, then explains why she wanted to support children's charity Warchild by donating 15 per cent of the proceeds from sales of the limited edition T-shirts to its projects in the Democratic Republic of Congo.

"I came across Warchild's work when I was in Kosovo, and I wanted to support them because they are working in the Congo and there are so many problems there," says Hewson. Although the country held its first free elections in four decades in July 2006, its people still face violence, looting and displacement.

In her soft, sympathetic Dublin tones, the kind that make you donate money to a cause before you even know what it is, she adds that "children are always the silent innocent victims of war and Warchild are just trying to stem the bleed."

She is sweetly excited about the T-shirts - she's wearing one with Chanel wedges, a black blazer and skinny black jeans - and her smokily made-up eyes brighten as she explains how nice and long they are. The fact that animal motifs are having a bit of a moment, (apes at Christopher Kane, wolves everywhere) was a happy coincidence, she says, as all she had in mind for their illustrator Jo Ratcliffe was something "raw and Africa-focused".

Hewson's interest in Africa began when she was 24, and she and Bono worked in refugee camps in Ethiopia for five weeks after Live Aid. She says she was "prepared for what it would be like when we were there, even though it was really tough, with terrible hunger and starvation and people dying every day. It was when I came back that I found it strange going into a supermarket, because I was overwhelmed by the fact that you could actually buy food."