To Peter Hilton, Alan was
... a very easily approachable man—though you always felt there was lots more you did not know anything about.
There was always a sense of this immense power and of his ability to tackle every problem, and always from first principles.
I mean, he not only ... did a lot of theoretical work, but he actually designed machines to help in the solution of problems—and with all the electrical circuitry that would be involved, as well.
He did, for instance, design a special machine to help Harry Golombek with the analysis of the particular Enigma system employed by the German motor torpedo boats.
But it also represented the essential truth about the Bletchley work, and Alan Turing was at the heart of it:
In all these ways he always tackled the whole problem and never ran away from a calculation.
If it was a question of wanting to know how something would in fact behave in practice, he would do all the numerical calculations as well.
We were all very much inspired by him, and he was a delightful person to work with.
He had great patience with those who were not as gifted as himself.
I remember he always gave me enormous encouragement when I did anything that was at all noteworthy.
And we were very very fond of him.