The mood took an uncomfortable turn not long after that when my day-long drinking partner made some broad statements about Muslims, and collective responsibility; he alluded to retaliation, without specifics; and he spoke as if confident that we all shared his urge to punish, to strike back. This seemed pathetic and futile to me, the bombers having obliterated themselves, and I disagreed strenuously, impressed with my own tolerance and ardent forgiveness – rather full of it, really. The other housemate sided with me and the day ended on an ugly note of disharmony.

I was at home during the commemoration of the tenth anniversary of the bombing. I don’t recall if this was a scheduled or unscheduled absence. Next door had not yet started its renovation; I woke mid-morning and switched on the TV after opening my first can, expecting Homes Under the Hammer. But instead there was a live broadcast of the ceremonies at St Paul’s Cathedral. I watched, disturbed at the mismatch between the ancient ritual and anachronistic dress happening now, and the memories of the very modern catastrophe then. And disturbed at the unsimple range of emotions brought up by the day, the date. Shock, anger, grief, yes, yes, yes. All those, of course. But also that strange sense of liberation when the day’s pattern is broken, and the comfortable comradeship of the beers at noon, on a workday; and the unpleasant way the day had ended; because to call that ‘unpleasant’, could it be inferred that I found something pleasant before then? Which meant awful guilt. I hated the way my housemate had held the bombers’ co-religionists to blame, the way he easily swung his anger around to face a whole community, our neighbours as well as our fellow Londoners and Britons. But I wished my own reaction was that simple and stupid. In the following days I heard the sirens in the streets, felt the tension.

For a year or two after the bombs, I occasionally had nightmares of being caught in an attack or other disaster on the Tube; trying to flee down lightless tunnels, being trapped in carriages filled with smoke, bodies everywhere. In the hellish summer of 2012, those nightmares returned to my waking mind, one of several choice scenarios served up to me as I lay shaking and sweating in bed, completely awake.

We want beginnings. Start late, finish early. Get stuck in. ‘X is running late, and here I talk about how rude their PRs are’, ‘X was born in blah and spent their early years blah-de-blah’, ‘I meet X in this or that restaurant or hotel and here are three paragraphs describing that setting in not-very-amusing detail’ – these are called ‘long drop’ intros and are frowned upon.

But what if a situation can only be understood with reference to the past? What if some behaviour just appears to be senselessly self-destructive without that reference?