Which was why, when I saw the sea of blue lights outside Baker Street Underground Station, it was a little bit like coming home. Rising out of the lights was the three-metre statue of Sherlock Holmes complete with deerstalker and hash pipe – there to oversee our detective work and ensure that it was held to the highest fictional standards. The metal lattice gates were folded back and a couple of PCs from the British Transport Police were tucked inside as if hiding from Sherlock’s stern gaze but more likely because it was freezing. They barely looked at my warrant card, waving me through on the basis that nobody else but a police officer would be stupid enough to be out this early.

I went down the stairs to the main ticket hall where the automated Oyster barriers were all locked in the open ‘fire’ position. A bunch of guys in high-vis jackets and heavy boots were standing around drinking coffee, chatting and playing games on their phones. That night’s routine engineering work was definitely not getting done – expect delays.

Baker Street opened in 1863 but most of it is retrofitted cream tile, wood panelling and wrought iron from the 1920s itself overgrown with layers of cables, junction boxes, speakers and CCTV cameras.

It isn’t that hard to find the bodies at a major crime, even one at a complicated scene like an Underground station – you just look for the highest concentration of noddy suits and head that way. When I stepped out onto platform 3 the far end looked like an anthrax outbreak. It had to be foul play then because you don’t get this much attention if you’re a suicide or one of the five to ten people that manage to accidentally kill themselves on the Underground each year.

Platform 3 was built in the old cut-and-cover system in which you got a couple of thousand navvies to dig a bloody great big trench, then you put a railway at the bottom and covered it over again. They ran steam trains back then, so half the length of the station was open to the sky to let the steam out and the weather in.

Getting onto a crime scene is like getting into a club – as far as the bouncer is concerned, if you’re not on the list you don’t get in. The list in this case being the crime scene log and the bouncer being a very serious-looking BTP constable. I told him my name and rank and he glanced over to where a short stocky woman with an unfortunate flat top was glowering at us from further up the platform. This was the newly minted Detective Inspector Miriam Stephanopoulos and this, I realised, was her first official shout as a DI. We’d worked together before, which is probably why she hesitated before nodding to the constable. That’s the other way you get into the crime scene – by knowing the management.