Spot the difference — the prototype hydrogen boiler looks very similar to the existing versions found in homes around the UK

The future of heating looks, admittedly, a lot like the present of heating. “It’s the most boring prototype ever generated,” says Tom Collins, from Worcester Bosch, standing beside his creation. “It’s just a white boiler box. Users will think it’s identical.” No one, he laments, finds boiler scientists interesting at parties.

But they should. His box is a key component in what — if it is successful — will be one of the biggest UK infrastructure revolutions of the century. And its key advantage is also what makes it boring: that for the user it changes almost nothing.

The burner inside is not the blue flame of natural gas but the invisible flame of hydrogen. When it combusts, all it makes is water. More than