How has the building stood the test of time? Did the vegetation work?
Bryan Avery: The acoustics have worked well, which was one of my main concerns. It is very quiet inside. There have not been too many technical problems at all. The only remedial work that I know about has been to the handrails of the balustrades. The staircases have light wells, to create a proper Pirenesian space. The balustrades were very thin and kids were sliding down the banisters on their way out, so they had to do something about that.
The building is due for a makeover internally, but if the standard of makeovers at the NFT is anything to go by, this should endow it with all the style and panache of a second-rate suburban multiplex.
The vegetation has been the biggest success. People had all sorts of reservations about whether the plants would survive in such a polluted environment, with bugs and so on. But it's all still going.
We have got jasmine, wisteria, clematis and ivy, and it plays a real role in absorbing noise and fumes. We've had one bug infestation but apart from that it's bearing up pretty well.
What would you do differently if you could do it all again?
Bryan Avery: If I could start from scratch, I would try to make the dome higher. It doesn't read much like a dome. So, it doesn't really look like a rotunda.
You have to get to the top of the bridge to see it. We had to use a French system for the roof.
It was the only one we could - nd that had a minimal upstand and would give us that double curvature. I think that you can get British systems now.
I am still trying to do other buildings that are totally vegetation. They should do this all over the South Bank. A bit of planting goes a long way.
If they're not going to get their act together and do something about all those buildings, then why don't they landscape it?
We have proven that plants can thrive in a hostile environment.
My real regret is about the image on the facade. Before we built IMAX, this was all public open space. It took two years to get agreement for the change of use, and there was a clear understanding that this was still very much a public building, which was serving a civic function. My intention was that the facade would be the canvas for a giant artwork that would say something about the South Bank, and would change every two years. The plan was to have a competition which would have something of the stature of the Turner Prize and would provide an opportunity for graphics to express itself on a grand scale. I was so relieved to get the first one up. It was by Howard Hodgkin and it cost £100,000. It was wonderful, even though Will Alsop said: 'It looked far better before that image went up.'
Having set the precedent, I assumed that it would happen naturally, but it didn't. I tried to interest various companies in resurrecting the idea. But I discovered last year that IMAX have signed a deal with an advertising contractor. They have discovered that it can earn millions as a billboard.