While I downloaded a sample of this book ages ago, it wasn’t until I was looking for another audiobook to entertain me on an airport run that I engaged with it. And how weirdly coincidental it is that I’ve now listened to two audiobooks in a row that require the narrator to read out a lot of transcript timecodes! First The Ink Black Heart and now this!

The coincidences don’t end there. Both books feature characters who are obsessed with an intellectual property. In this case, it’s a series of books by an out-of-fashion children’s author which are reputed to contain a secret code…

A further coincidence arrives in the shape of the year 1983. Nothing to do with The Ink Black Heart, but I’ve been watching The Gold on BBC iPlayer (very good), which is about the Brinks-Mat robbery, which took place in November 1983. Meanwhile, I’ve also been recording episodes of my forthcoming audio version of The Obald, which is set in… November 1983. And in The Twyford Code, young Steven Smith stumbles across a copy of an Edith Twyford book on the top deck of a bus in… 1983.

Steven is an old lag, just out of prison and trying to go straight. As part of his rehabilitation, he’s using an old iPhone 4 to record his story, and Hallett’s novel consists of the transcripts of those recordings, complete with glitches, [background noise detected], bleeped out swearwords and mistranscriptions. “Kos” for ’cause, and “mustard” for must’ve.

Does this sound promising? I wasn’t sure at first. The voice doing the narrating seemed kind of flat, and there were a few moments where I felt he’d missed an emphasis. What’s THIS for instead of What’s this FOR, that kind of thing. Easy mistakes to make. Even reading out things I’ve written, I find myself getting the odd emphasis completely wrong. But beyond the mistakes in emphasis, I felt like I could hear in my head what Steven, out on parole, would sound like, in terms of a working class London accent, and yet the narration made no attempt to capture that (obvious) voice, nor any of the other characters.

But then you have to ask yourself, who is the narrator of The Twyford Code? Because, sure, Steven is speaking into his phone, but then the software is (almost completely accurately) transcribing the recordings, which have been printed out and sent to someone, who is reading them. It’s a proper old mise-en-abyme, my favourite literary trope. So nice!

And once you realise that “the narrator” is somewhere in that labyrinth, the flatness of the voice seems right. Which is before you get to the “Enid Twyford” books, which are in there somewhere. Twyford is an analogue for Blyton, obviously, but her books about six children solving crimes are also supposed to contain hidden messages. So it’s all texts within texts, and great fun.

Steven, dyslexic, was in a small English class at school for the struggling readers, and when he found a children’s book on the top deck of a mysterious bus, it ended up in the hands of his teacher Miss Isles, who apparently grew so obsessed with the Code that she organised an unofficial school trip down to Bournemouth, where Twyford lived during World War 2.

Now, forty years later, Steven is trying to remember what happened on that trip, so he’s looking up other members of the class and enlisting the help of a kind librarian, recording everything on an old phone given to him by his son, with whom he has had no relationship, thanks to his criminal past. Going straight isn’t easy; there’s always the sense that the fate of Miss Isles isn’t the only event from his past that concerns him.

This was a properly entertaining, very clever, puzzle box of a book. I enjoyed the audiobook so much that I immediately started listening for a second time.