I have been suspected of utopian thinking more than once, and particularly when five years ago I proposed the elimination of nuclear weapons by the year 2000 and joint efforts to create a system of international security. It may well be that by that date it will not have happened. But look, merely five years have passed and have we not actually and noticeably moved in that direction?

Don’t write in public places. In the early 1990s I went to live in Paris. The usual writerly reasons: back then, if you were caught writing in a pub in England, you could get your head kicked in, whereas in Paris, dans les cafés . . . Since then I’ve developed an aversion to writing in public. I now think it should be done only in private, like any other lavatorial activity.

As I was starting my academic career, it was almost considered to be a negative signal to your career to get involved in politics ... But to me that was a sign you were doing something useful.

Instant information about everything and everyone often allows an individual opinion to compete with consensus and paranoia with evidence. It is a time when one blunt honest statement can finish a life-long political career, and one opinionated journalist can bully a government or a royal family. Science is not immune from such pressures. For example, how many Nobel prize-winning experiments – you think – would have been stopped, if ethics or health-and-safety regulations at that time were as zealous as they are today? I can think of more than a few.