Without speaking, we worked together. Pierce hit the greatest concentrations of flame, and I swiped and stamped and snuffed the leftovers and fringes with the blanket. We fought for what felt like an age, though it had been less than ten minutes since he had sparked the lighter, and when we were sure the danger was past and all the windows were open to thin the smoke, we splashed across the sodden floor to the couch, coughing and weeping and spitting.

‘Why did you do that?’ I said, as soon as it was possible to croak out words. ‘You could have killed us.’

‘I’ve been meaning to take that down for ages,’ Pierce said, with a nod towards the map. It was a ruin, two-thirds of it gone, only west London hanging on, damp and sagging from its pins. The cork tiles that had supported the map were blackened and scarred, some no more than charcoal, others fallen away to reveal the shocking, floury white of spalled plaster. A ridge of debris lay along the line of the skirting board, in a wide puddle of sooty water, soaking into a rucked, grimed rug. Despite the open windows, the room stank of smoke, and a haze of particulates perverted the light.

‘The people downstairs are going to be cross,’ I said.

‘I never see them,’ Pierce said. ‘Anyway, they can’t be cross. I’ve had a house fire. A terrifying accident. They’ll have to be sympathetic. There are rules.’

Yes, malign sympathy. There it was, the sensation I had felt in the morning, sitting breathing the exhalations of my own destroyed house. The lure of freedom. But thought of it was cut short by another coughing fit.

‘What were you saying about being followed?’ Pierce asked. ‘Something about the fumes getting into your head …’

I coughed again, and again, trying to dislodge the sack of charcoal briquettes that was crammed in my throat. I could taste blood, a little, and felt as if I were in the late stages of a chest infection. Light-headed, too. Perhaps I should have taken the paramedic’s advice and gone to hospital; perhaps I should go now.

‘It’s gone now, isn’t it?’ I said, unsure of how to approach the topic and fearful of the answers. ‘The column of smoke we followed on Tuesday. It’s gone – you couldn’t see it today?’

‘Today? It had cleared up the day after,’ Pierce said. ‘They put the fire out. Or it put itself out. From the look of the place there was nothing left to burn.’

‘That’s what I thought,’ I said. ‘The thing is – I can still see it.’

‘Still see what?’ Pierce asked. ‘The smoke column?’

‘Yes,’ I said. ‘I’ve been able to see it ever since. No matter where I am. At night, even. As if it has been following me around. And getting closer, street by street.’

Pierce didn’t say anything. I had his attention, at least, although it was impossible to read his gaze.