Introducing Luther - with love to Detective Columbo
The character that became Detective Chief Inspector John Luther was pinging round my head long before he had a name - or I had any idea how to use him.
He started as means to connect two ideas from different genres within the broad church of crime fiction. Luther has some of the Sherlock Holmes about him - some of that disinterested analytical genius.
But he's also got the emotional complexity and moral ambiguity more commonly found in the psychological thriller. It seemed to me that combining these properties - deductive brilliance and moral passion - in one man could make for a powerful and damaged, deeply heroic character.
Lieutenant Columbo was rarely at any personal risk (because that's not we wanted to see) and we knew he'd always get his killer in the end.
What we didn't know was how - which played a big part in making that show so incomparably satisfying.
The inverted detective story format hadn't really been revisited since Columbo ended, not that I know of anyway. So I thought it might be exciting to portray it as a kind of psychological duel between this driven, half-mad cop and the depraved criminals he hunts.
So we know who Luther has to catch. What we don't know is how on earth he's going to do it.
The process of making the show, from writing the scripts to seeing it reach the screen, has been exhilarating and sometimes petrifying. As these things go, Luther moved very quickly indeed. At times it felt like I was strapped to the nose cone of a rocket.
In the weeks leading up to take-off, I could feel the constant, seismic rumble of all those barely reined-in pounds per square inch of thrust. And once it started to actually move, all I could do was hang on and hope the teeth wouldn't get rattled from my head.
In a situation like that, you don't get writer's block. Or sleep much, either. But I did get to work with people I like, admire and trust. We were a proper team and we were on a mission. I revel in that feeling of camaraderie.
The cast is so good I was terrified of meeting them as individuals, let alone as an ensemble - but that's essentially what happened. With the exception of Indira Varma (who couldn't be there) I met them all at the episode one table-read, a kind of first read-through rehearsal, where I was a gibbering wreck.
That night we went out for drinks.
The first hour or so, talking to Saskia Reeves, all I could think was: 'I'm talking to Saskia Reeves!'.
By 10pm, I was a few gin and tonics into the evening and Warren Brown - who plays Detective Sergeant Ripley - was doing his Lily Savage impression. I was able to relax somewhat and just revel in the fact that we'd brought together such an astonishing cast.
People often ask me what was the best moment, but to be honest it's hard to elect just one or two.
In the run-up to production and during production itself, I spent a lot of time laughing with my colleagues: in retrospect, given the time pressures involved, that seems remarkable. But a particular high point has to be casting Idris Elba.
We wanted the show to be special, so when it came to casting our leading man we'd decided to be ambitious, to set the bar high, thinking: don't ask, don't get.
Idris was on the list... because Idris is pretty much on everyone's list. But his name was waaaaaay up there, up above the cloud line. So when I got the phone call saying we'd got him - that was a good moment; as good as these moments get, I think.
Then there was watching the rushes at the end of the very first day's shooting. It had taken place outside episode one's "Morgan House" crime scene.
I saw Idris walk into shot, duck under the tape, and I thought: 'There he is, then. That's Luther.'.
I love John Luther, naturally. But I also love unreservedly the character of Alice Morgan. In fact, on that first night out with the cast I seem to recall telling Ruth Wilson (who plays her) that in many ways I considered Alice to be the perfect woman. She looked at me, it has to be said, with a degree of horror.
Alice was a formidable role - chilly and flirtatious, murderous and vulnerable, high-minded and caustic, sometimes in the same sentence. But Ruth makes her absolutely real, and utterly riveting. There's a moment in episode four where she truly frightens me.
I was on set when Idris and Ruth filmed their first scene together. It was a spine-tingling event - but I don't think it's good for me to hang round on set, because that's just not where a writer belongs. So I made myself scarce and let them get on with their jobs.
As for what you can expect from Luther and where he goes next ... well, if I told you, it wouldn't be a surprise. Let's just say, the pressure on him doesn't let up. Not for a second.
Neil Cross is the writer of Luther. Luther starts on BBC One at 9pm on Tuesday, 4 May