The back wall of the study was hung with a couple of framed watercolours that Nick had said he valued because they were so astonishingly ugly that they demonstrated immense talent. I had laughed then. Now I lifted them away and smoothed my hand over the plastered wall. There was nothing. Neither was there anything of interest behind his writing desk or any indication of a ceiling cavity. I drew back the curtains and checked behind them – and my eye fell on something I hadn’t seen before. About half a metre up the wall, hidden behind the material, there was a large square wooden panel, with sides about forty centimetres long. I couldn’t recall seeing anything like it in any other room. I knelt down and felt around it.

The sound of movement from Hazel’s room made me stop. The subsequent silence told me that she wasn’t coming, however, so, after first taking the precaution of locking the study door to make sure, I went back to running my fingers around the wood. There was a hair’s breadth of a gap between it and the wall but the edge was too thin to get a grip on. I looked through Nick’s desk for something I could use to prise it away. An old pen with a steel nib looked like it might work, and I stabbed it into the thin gap, but the only effect, as I tried to lever the panel away, was to bend and snap the nib. I needed something more solid.

I hunted through drawers, tossing aside envelopes, an ashtray and a few notebooks. Then, at the back of one, I found what I needed: a brass ruler, tarnished at the edges and its numbers rubbed away, but fundamentally strong.

I returned to the floor and shoved the ruler in hard behind the wood. It went in only a few millimetres, though, and, try as I might, that produced no leverage. I grabbed a hardback book from Nick’s shelf – a medical textbook detailing the effects of hormones – and placed it against the end of the ruler. I shoved with all my weight and felt the brass slip in further, far enough to act as a lever. The wood didn’t want to move; it was jammed in tight; but, little by little, working the metal back and forth, and then doing the same on the opposite side, I managed to draw the panel slightly towards me and into the room. Eventually, I could grip it properly and rip it away, to leave a gaping, rough hole in the plaster and a little cloud of dust seeping through the air.