Everybody’s a slave to their habits, little behavioural tics that we’re often barely conscious of – and even if we are, we probably couldn’t change them if we wanted to. Bev always sleeps on the left side of the bed, Guleed always puts three sugars in her black Americano, and the Faceless Man has two ways of killing people he wants dead. If it’s just business then he favours the quiet and forensically invisible approach – an apparent suicide or a sudden heart attack. If he’s pissed off or wants to make an example, then it gets very messy indeed. Having your dick bitten off or your bones set on fire from the inside are only a couple of the merry ways that we know of for certain.

We’d been reluctant to employ a forensic psychologist because of the well-founded fear that they might section us for believing in fairies. But you didn’t need a degree to figure out that the whole ‘making an example’ aspect was actually bollocks. It was simply an excuse to do horribly inventive things to his fellow human beings.

You certainly had to wonder what poor Aiden Burghley had done to justify having his face nailed to a tree in a small park in suburban South London.

Well, not nailed exactly. Removed from his skull and attached to the trunk at head height – my head height, I noticed – not Aiden’s, who had been shorter.

Downham Fields was a low green mound that formed the centrepiece of Downham Estate – a 1920s housing estate in Lewisham. Built by the London County Council as a low-rent version of the then-fashionable garden city idea, it was to house the ‘respectable’ working class of Bermondsey and Rotherhithe in six thousand unremarkable semis. Unremarkable, of course, providing you’d grown up with such luxuries as indoor plumbing and back gardens. To ensure that the hoi polloi were properly appreciative of the largesse bestowed upon them, the LCC employed inspectors to enforce acceptable standards of cleanliness and order. Although this wasn’t enough reassurance for the residents of a nearby private estate, who insisted on a two metre wall topped with broken glass to maintain a suitable degree of separation.

The low hill in the park was crowned by a Catholic church and attached school and further down the slope was a rectangular copse of trees which I totally failed to identify. Just inside the treeline, in a surprisingly compact area, was what was left of Aiden Burghley.

Bromley MIT had already done a preliminary canvass of the area, plus house to house and CCTV, before gleefully dumping it all on Nightingale, me and Stephanopoulos and skipping away with happy cries. They wanted nothing to do with it. I could empathise – neither did I.