Let me introduce you to Finkelstein’s law of political decisions. You are forever making decisions before you know you’ve made them. Most choices you make are the prisoner of a smaller choice you made earlier.

At some point, obviously, you make the original determination from which consequences flow, but you usually don’t realise it when you are doing the determining. By the time you reach your destination, and it is too late to turn back, you have almost forgotten those light first steps you took onto the path.

I could give you loads of examples from world history — Vietnam, for instance — and loads from my own history — ending up living my life in Pinner, for reasons that are obscurely related to the