Professor Alan Ahearne:

I did not say at any stage that I was absolutely certain that this was going to happen. I did not have a crystal ball. All I could do, and it was what I did, was to look at other countries' experiences and say there was a risk. I tried very reluctantly to put some numbers on over-valuation. I think I mentioned, possibly on the "Future Shock" programme, a figure of 30% and I gave a figure of 20% to other people. It was very difficult to put a number on it but it was a significant risk. The problem I saw with it was that even if one thought there was only a 30% chance of a crash and a 70% chance of a soft landing, the effect - that is, the devastation caused by the crash - would be so large that one would have to take that into account. One cannot always make policy based on what one expects to happen. One has to look at the distribution of risks.