Anyway, says Grimshaw's partner Chris Nash - directly responsible for the Battersea designs - Conran has got the wrong end of the stick. "The notion that Battersea will be a funfair is quite wrong. Making it a funfair doesn't work commercially. I hope it becomes a fashionable, cool place to go." He envisages, spas, health clubs, bookshops, nightclubs - all with "opportunities for unparalleled views across London" from the upper floors with their new glass west wall. Nash uses the cathedral analogy: elegant paired columns will rise the full height of the old boiler hall - the size of a London square - to the new undulating roof high above. Light will pour into what was once - before it fell into ruin - a dark, crowded space. And as for the famous control room overlooking that hall, with its banks of 1930s switches and dials - all still present and correct, I've seen them myself - that would make a great restaurant, Nash reckons. Conran might be interested.

For Grimshaw himself - who works quietly on as he has always done in his glass-walled office, seemingly unaffected by his rapidly growing fame - the key to Battersea and Eden are the strong-minded clients behind each of them. Eden has the bustling, publicity-manipulating Smit; Battersea has Victor Hwang, enthusiastic hands-on head of the Hong-Kong-based property dynasty that owns the power station. "They're both visionaries in a way, and they both believe in their subject. They do it with conviction. There's an underlying seriousness to both projects."

Grimshaw is quite a chap for underlying seriousness. There's never been anything remotely flippant about his painstakingly crafted, entirely modern architecture. Now that he's working on a titanic scale, nothing much has changed. Down at the Eden Project, there's an exhibition of full-size bits of the great domes - complex lightweight steel joints, swatches of the transparent foil he is glazing it with in preference to glass. The visitors, I note, like to handle, almost fondle, these pieces. Grimshaw would like that.