When I was young I would often cycle to Eynsford, a small village in the Shoreham Valley about two hours away by bike. I usually went by myself. I spent hours in the river with water up to my knees filling a jam jar with tiddlers. I got to know the river quite well. I loved the way it would form itself into little eddies. These little vortices appeared suddenly out of nowhere and then quietly slipped away again as quickly as they had come.

One game I used to play was to look at a piece of water, concentrate hard, and tell it to eddy. I spent one morning trapping eddies and I almost believed I could catch eddies in my hand.

I have a peculiar brain. I am not good at remembering things. My brain doesn't organise itself that way. If I am to remember something I have to be able to work it out from first principles. I can learn things by heart...I remembered all my lines in Pinter's Dumb Waiter...but however many times I learn Wordsworth's I wandered lonely as a cloud or Coleridge's Rime of The Ancient Mariner it is not there a week later.

It was partly for this reason that I jumped at the chance to play a proper talking and singing role in The Pirates of Penzance. I wanted to see how I would cope...not whether but how. Yet I've always been very quick with numbers.

I have met my match only once. Les Smith...from a Jewish family in Manchester. He had worked the local markets with his father ever since he could hold a three-penny bit in his hand. We were in the middle of the Belgian Congo waiting for a bridge to be mended and organised a Grand Challenge. He definitely had the edge. There was only a split second in it. But it was a consistent edge.

I worked hard in my second and third years at Cambridge. After the fright at the end of my first year when I was nearly thrown out, I put in enough work for a good upper second and was a little disappointed to receive a lower second. Dick Tizard let me see the results of my various papers. There was hardly a second among them. I either got a first or a third. On Thermodynamics and Materials my marks were among the best in the university. On Applied Mechanics and Fluid Dynamics they must have been among the worst…I failed.

On Fluid Dynamics it was not quite Noll Poäng...but as near as dammit. I knew I had done badly. None of the right questions came up...I had spent a lot of time analysing previous years' questions and working through the books of model answers...and I could remember nothing that might help me cobble together some half sensible responses to the questions that did appear. This happened not once, but twice. In both the second year and the third year exams. Fluid Dynamics has intrigued me ever since. I read it as well as I studied any other subject. But the problem was that it was wrong.

Fish dart. A flick of the tale and they're a dozen yards away. You can't explain this in terms of Turbulent Layers and the Aerodynamic Theory of an aircraft wing. And Vortices? Not interesting. No use for them. Just cause problems for the Oil Industry. Electrical engineers know about eddies because their transformers melt unless they make them out of wafer-thin metal sheets to eliminate them. Leonardo da Vinci was fascinated by vortices. Pity electricity wasn't around in his day.

Then there's gyroscopes. Anti-gravity forces created by spin on an axis at right angles? What is this? What happens in other fluids than air? What about oil...or water...or out in the vacuum and weightlessness of space? These things interested me. But nobody wanted to know. Nobody had any theory about this. There were no formulas for students to learn by heart.

Fish, Gyroscopes and Eddies might have given me a first on Fluid Dynamics. But flow in pipes, Bernoulli’s Theory and the mechanics of plugholes were just not my scene. As I tried to go back to first principles I found either a void or a comedy of errors.

Let us consider the ideal situation where there is no this and no that and the moon is made of blue cheese. Then under this set of circumstances we can say that this force acting on that surface is represented by the equation F=ax +b where x is unknown and a and b depend on the time of the week. It set me up nicely for Economics though.