Each my book feels like my last book. And then I think, like a dedicated alcoholic, that one more won't do me any harm.

The Secret Intelligence Service I knew occupied dusky suites of little rooms opposite St James's Park Tube station in London.

It was a charming fantasy of romantics that the spies would stop spying, that political conflict would end and politicians would tell the truth. Unfortunately that has not been the case.

Look... we're getting to be old men, and we've spent our lives looking for the weaknesses in one another's systems. I can see through Eastern values just as you can see through our Western ones. Both of us, I am sure, have experienced ad nauseam the technical satisfactions of this wretched war. But now your own side is going to shoot you. Don't you think it's time to recognise that there is as little worth on your side as there is on mine?

Why did I desert Labour? Total bloody disillusionment. The party was a corpse. It had no ideology, it became detached, old, spineless and needed to go.

The Spy Who Came in from the Cold was the work of a wayward imagination brought to the end of its tether by political disgust and personal confusion. Fifty years on, I don't associate the book with anything that ever happened to me, save for one wordless encounter at London airport when a worn-out, middle-aged military kind of man in a stained raincoat slammed a handful of mixed foreign change on to the bar and in gritty Irish accents ordered himself as much Scotch as it would buy. In that moment, Alec Leamas was born. Or so my memory, not always a reliable informant, tells me.

Americans believe that if you know something, you should do something about it.