It all started with mosquito nets. Or, no, with guinea worm filters. Or, before that, with a million yards of wool in the mountains of Sweden.

Or, taken back another generation, to uniforms for hotel and supermarket workers.

There are plenty of charitable foundations and public agencies devoted to helping the world’s poor, many with instantly recognizable names like Unicef or the Gates Foundation.

But private companies with that as their sole focus are rare. Even the best-known is not remotely a household name: Vestergaard-Frandsen.

Its products are in use in refugee camps and disaster areas all over the third world: PermaNet, a mosquito net impregnated with insecticide; ZeroFly, a tent tarp that kills flies; and the LifeStraw, a filter worn around the neck that makes filthy water safe to drink.