This might make them sound stuffy and orthodox – brittle mannequins of small-minded propriety cursed with a dissolute son. (My younger sister, a pharmaceutical chemist at Sheffield University, has done a little better at cleaving to the path.) Not true and not fair. They were never less than loving and supple in their accommodation of my occasional efforts to remove myself from the path. Their belief in the path manifested itself more subtly. Any unhappiness, for instance, could be diagnosed as deviation either past or planned. Miserable at school? I needed to treat it as a means to an end, the end being university. Restless and unmotivated at university? Again, its only purpose was as a step leading to the next step – head down, push on. Unable to save a mortgage deposit? Perhaps I should consider getting a more solid, more proper job – or moving back to Two Hours Away (by the faster train), the southern provincial city in which I was born. Love life problematic? Perhaps a Proper Job would yield more suitable candidates. None of this advice was delivered with self-righteousness or coercion, it was all meant honestly and kindly. And who could blame them for their belief in a system that had served them perfectly?

But just as the Correct Route Through Life had supplied its own built-in justifications, its completion had robbed it of purpose. My parents had spent their whole lives working dutifully, rewarded daily with the certitude that they were doing the right thing. The arrival of the real reward – comfortable retirement, two decent pensions, mortgage paid off, children through university and out of the house – had deprived them of the satisfaction of dogged, stately progress.

They went a little crazy.

When I was growing up, I never saw my parents argue. They disagreed at times, or frowned at each other, but never did they engage in that basic ritual of relationships, the big argument. Not in my sight, anyway. I have no inkling of what script discussions or creative disputes went on behind the scenes of their performance as Mum and Dad. But on stage, they were pros.

In the first year after their retirement, they argued: long, flamboyant arguments with epic scope, stirring chiaroscuro and elaborate, intertwined plots and subplots. Late in life, they found that they shared a gift for holding a really poisonous row.