Grimshaw says: "I bullied Frank into it. He really was wearing himself to a frazzle with the business. I told him, "Look, Frank, you are going to have a heart attack if you're not careful. You're going to have to do something with your life."

As to why it takes the form it does - why the Spine? - it all comes down to the view, says Grimshaw. "There was a bit of a tatty old house on the site before, but it had a little gable window overlooking the view - which is just as spectacular in winter as it is in summer. I stood there and thought, I've got to have some kind of viewpoint like that. That was the start of the idea of walking straight through the house, and out to the view. Because the land drops away, the essence of the house is that progression from being at ground level at the entrance, to being suspended in mid air at the other end."

Designing a house is an intense activity, and this one was definitely a labour of love rather than a profit-making venture. Grimshaw observes that a £1m house such as this takes as much architectural effort as the average £10m commercial building. Perhaps the most surprising thing about it all, however, is that it cost about the same to build as a conventional (German) house of the same size. "It's surprisingly economical," says project architect Martin Wood, sounding surprised himself. The obvious expense of the spine was offset by the economical, almost factory-like steel-frame structure of the rest of the house. In total it came in at around £100 per square foot.

Daniela Blase answers the video doorbell. The photographer is setting up. Frank is at the factory, this being a Saturday morning in Germany. He's still working too hard, but is promised for lunchtime. All of which information is a little hard to take in at first as, when the door swings open, you feel like Jonah in the belly of the whale. The timber ribcage undulates away from you. It's faintly scented, like a pencil box. At the far end, a bright spot of light reveals the verdant landscape that the house overlooks. You walk towards this and the view opens up. You have come in at ground level but, as the land drops away, you find yourself perched up high at the front of the house. Wooden steps lead down to the living area, or up to the mouth of the whale. Its jaw juts out of the front of the house as a boat-shaped balcony. What with that and the aeroplane fuselage/rocket/sexual imagery (and from certain angles you are also reminded of insects and crustacea), you are standing in the middle of one great big multivalent image. This is Grimshaw country, all right, the seamless blend of the organic with the technocratic.