But now sustainability is such a political category that it's getting more and more difficult to think about it in a serious way. Sustainability has become an ornament.

At that time [90th in Lagos], if you drove through the city, you drove through a foreground that always seemed to be incredibly dramatic and incredibly agonised - smoking, burning, incredible compression. In the first year we stayed on the ground and went everywhere. But then in order to discover whether this was the whole story, we rented a helicopter. And we began to understand that this is not chaos but a highly modern system that had been abandoned, then at some point went into reversal, then slowly came out of it.

When shopping was still connected to the street it was also an intensification and articulation of the street. Now it has become utterly independent - contained, controlled, surveyed.

Our office acts like a kind of educational establishment and we are very careful who we educate.

Not many architects have the luxury to reject significant things.

In Lagos there's a really strong case to resurrect strong parts. Embedded in all of it are some amazing pieces of planning, amazing pieces of engineering and interaction. For instance, the campus of Lagos University is stunningly beautiful, efficient and generous, and that needs to be recognised and preserved.

We live in an almost perfect stillness and work with incredible urgency.