I have been asked to say why and how I came to write my play "Breaking the Code". I must make it clear from the very beginning, ladies and gentlemen, that I know very little about mathematics. I had no urgent desire to write about the subject. And then, one day in 1983, while reading The New York Review of Books, I came upon an essay about a newly published biography – by Andrew Hodges – of a man called Alan Turing. I was astonished to find that this man – one of the very few human beings who can be described accurately and correctly as a genius – this man had led a life that a writer of fiction would not dare to invent. And I ashamed to admit that I had never heard of him. I bought Andrew Hodges' book and read it with growing excitement and admiration. I urge anyone who has not read this extraordinary biography to do so without delay. Andrew Hodges is not only a eminent mathematician, he is also a writer of rare talent and sensitivity. One of the most trivial facts I learned about Turing was that his favourite film was the Walt Disney movie "Snow White and the Seven Dwarfs". And, in a curious echo of this film, Turing killed himself by eating a poisoned apple. Those two facts taken together seemed oddly moving. And it was for that rather silly and totally insignificant reason that I decided to try to write a play about this very remarkable man.

Let me just tell you very briefly about Turing's life. He was born in 1912 – went to Sherborne School (a fairly typical English public school) and then to Cambridge. At an early age he showed an astonishing grasp and understanding of mathematics and when he was only 22 he was elected a Fellow of Kings. He became interested in the idea of 'Thinking Machines' and wrote a highly influential paper called 'On Computable Numbers'. During the Second World War he was sent to the secret decoding establishment at Bletchley Park, where he played a key role in breaking the supposedly unbreakable Enigma Code – one of the most crucial factors in the defeat of Hitler. It must have seemed then that Turing's future was assured –- with a middle- age laden with academic honours and public recognition. But Turing was a homosexual –- which in those days was a crime in Britain. In 1952 he picked up a young man on the street, took him home and took him to bed. Subsequently, Turing's house was broken into and burgled. Turing suspected that the young man was involved and when he reported the burglary to police, Turing rashly revealed his own homosexuality. Thus he found himself a criminal, was arrested and sent for trial. He was found guilty of "gross indecency" –- a quaint English legal term meaning mutual masturbation –- and had to endure the humiliation of sex drug therapy. But Turing was a resilient man; he seemed to find a new happiness in his work and amongst his circle of loyal friends. And then –- quite unexpectedly –- he took his own life. He dipped an apple in cyanide and ate it.

It was never my intention to write a straightforward biographical play about Turing. There were things about his life that I reacted to personally – and, of course, a writer always searches for a personal involvement with his subject be it entirely imaginary or based on carefully researched fact. For one thing, Turing was a man flawed by a Jungian gap between thinking and feeling. The critic Nicholas de Jongh pointed out that half of Turing's tragedy –- and this applies to both heterosexuals and homosexuals –- was that he was driven by his sexual energies but could not relate them to his intellectual life. I wanted to explore this gap between thinking and feeling. Also –- and this is particularly relevant to this weekend's symposium –- I wanted to use mathematics as a metaphor. Since I'm always very wary of writers who attempt to analyse their own work, I will let somebody explain what I mean. Here is what Tony Solomonides wrote in the journal, 'Science as Culture'. "Scientists and nonscientists alike have at various times extended scientific metaphors in their construction and interpretation of human affairs. Darwinism is used to justify a form of naked capitalism, red in tooth and claw, as a natural economics; elsewhere relativity has been made out to mean that "it depends on your point of view". Hugh Whitemore has Turing doing something similar with his own field: here is mathematics, reliable knowledge; here is morality, rife with uncertainty, even prejudice. If the most powerful statement in modern mathematics only serves to delimit the very power of mathematics itself, is not some doubt called for to temper the arbitrary certainty of the law? More intimately –- and more poignantly –- if fresh thought is required in the solution of each new problem in mathematics, how can a detective sergeant fail to recognise the same need in the application of the law?" So wrote Tony Solomonides in "Science as Culture".

Quite obviously the Alan Turing story was marvellous material for a play. I was told that the actor Derek Jacobi wanted to appear in a contemporary role, following his enormous success as Cyrano de Bergerac. A producer friend of mine introduced me to Jacobi and I told him of my idea. Jacobi was extremely enthusiastic, and I decided to acquire the dramatic rights in the Andrew Hodges biography. But this was not quite as easy as I had anticipated. Mr Hodges was not terribly keen on the idea of a play being made from his book; he would have much preferred a movie. But luck was on my side. I had a play called "Pack of Lies" running very successfully in London. I took Mr Hodges to see it, and was delighted to observe that he was suitably impressed by the sight of a packed theatre responding with prolonged applause and cheers. An agreement was reached between us and I embarked on trying to turn his book into my play. This proved to be extremely difficult. A year went by as I struggled to find a suitable dramatic form. During this time it became very clear that in order to represent Turing's life on the stage, the audience must be given some understanding of his work and this meant that I would have to understand it myself. A daunting prospect for a mathematical dunce who struggles to calculate the tip in a restaurant. But I persevered. Andrew Hodges spent many hours patiently explaining some of the most important aspects of Turing's work –- and slowly, very slowly, I began to see the light.

Let me read you a speech in which Turing describes his own awakening to the excitement of mathematics. This is one of the first speeches I wrote as the play took shape – and I hope you can see how a non- mathematician like me was able to relate to the young Turing's intellectual voyage of discovery.

"When I was a child, numbers were my friends. You know how it is; you know how children have their own secret make-believe friends; friends who can always be trusted – dolls or teddy-bears or some old piece of blanket they've kept and treasured since they were babies. My friends were numbers. They were so wonderfully reliable; they never broke their own rules. And then, when I was about nine or ten, somebody gave me a book for Christmas: 'Natural Wonders Every Child Should Know'. I thought it was the most exciting book I'd ever read. It was, I suppose, looking back, a sort of gentle introduction to the facts of life; there was a lot about chickens and eggs, I remember. But what the writer of that book managed to convey was the idea that life –- all life –- is really a huge all-embracing enterprise of science. There was no nonsense about God or divine creation. It was all science: chemicals, plants, animals, humans. "The body is a machine," he said. How exciting it was to read that! What an audacious, challenging –- rather naughty –- idea that was. He made life seem like a thrilling experiment. And I longed to take part in that experiment."

When Derek Jacobi read the finished text he was initially enthusiastic and plans for the production went forward smoothly. But then, barely a month, before rehearsals were due to begin, Jacobi telephoned me and asked me out to dinner. As we sat in a French restaurant in Soho, he expressed grave misagivings about the play. "I don't know how to do it," he said. He couldn't believe that an audience would be interested in the mathematical material and feared that the long speeches about Turing's work would kill the play stone dead. In my heart, I had similar fears. No matter how experienced one may be, one can never predict how a play will be received by an audience. Consequently –- and wisely –- one always fears the worst. But as we sat there, drinking red wine and anxiously considering what we should do, I remembered the passion with which a mathematician had once spoken to me about his work. I looked across the table and remembered the passion with which Derek Jacobi had delivered the fiery speeches of Cyrano de Bergerac. Quite suddenly I realised that these two passions were one. There is no division between artist and scientist, poet and mathematician. I told Jacobi what I was thinking and it seemed –- immediately –- to unlock something in his imagination. Although still anxious about the eventual fate of our play, we would proceed.

After this momentous supper in Soho, Jacobi and I went away on holiday; I on safari with my teenage son, Jacobi to the sandy beaches of the Caribbean, where he learnt the immense role of Alan Turing – and thus dazzled us all by being virtually word- perfect on the first day of rehearsals. Like most productions our play was premiered in a provincial theatre, safely hidden from the scrutiny of the London critics. As the first night approached all the fears that Jacobi and I had shared in that Soho restaurant returned to haunt us like horrid ghosts. The hour of reckoning had arrived. The audience settled themselves into their seats. The play began. To our amazement, they listened. The long speeches, during which we feared that people would be bored and restless, were received in an almost rapt silence. What's more, I received a large number of letters urging me to insert more scientific material in the play. This I did before we opened in London. As the weeks and months went by, there were even more requests for additional scientific and mathematical detail, and so the text was further revised before the play opened on Broadway.

I had expected the play to have a shortish limited run. In fact, "Breaking the Code" ran for ten months in the West End and almost as long on Broadway. It has been translated into many languages and has been seen literally throughout the world. Earlier this year it was produced in Buenos Aires. In a few months time, it goes to Paris. A film version was made and won a shelf- full of awards. I mention this –- not, I hope, immodestly -- merely to point out that success can be achieved without compromise and without asking the audience to leave their brains with their hats in the cloakroom when they enter a theatre.

Finally, as an epilogue, let me tell you what happened when the play was in Washington, at the Kennedy Center. It had been a great success. Leonard Bernstein had prostrated himself in homage before Derek Jacobi. I was in my hotel room, enjoying a brief moment of triumph. The phone rang. It was a leading Hollywood producer. "Your play is a masterpiece" he said, "get on a plane and we'll talk about making it into a motion picture." And he named a colossal sum as a potential fee. Riches, at last, seemed to beckon. "Just two things," he said. "What's that?" I asked. "I don't want this guy to be a faggot and for God's sake cut out all the mathematics."