Do we write procedurals about the daily work of a butcher? A landscape gardener? An accountant? Some occupations might lend themselves to narratives – a spy, an adventurer, a doctor, a film star – there are books about them all. But the work of police as they go about investigating a crime is of endless fascination to both readers and writers. Dozens of police procedurals are written and published every year. I have often wondered how many of them are read by police officers, and what they think of them. But I wasn’t too keen to find out what this police officer thought of my novel. Not that one.

The Tanglewood Mystery was not my first book, nor my second, but it came early in my career. I now thought the title was dull and unoriginal: ‘Tanglewood’ was the name of a business complex where the murder took place. A detective serjeant was given the job of sifting through the evidence to establish how the killing had happened. Meanwhile, his career was in jeopardy because he had a secret and uncontrollable addiction to gambling. His move towards an answer to the murder mystery ran in parallel to his coming to grips with his addiction. The idea, the secret method of the killing, was good, as was the way the detective arrived at the solution by calculating odds and risks, but the telling was pedestrian. I’ve written better since.

‘I liked The Tanglewood Mystery,’ she said. ‘Clever and original.’

‘You didn’t find it a little slow? Did it seem unconvincing to you?’

‘Not at all. I wanted to find out what happened. The only thing is – have you ever worked with a forensic police team?’

‘Not directly. Actually, no, not at all.’

‘Have you ever thought of working with a police adviser?’

‘Was the book that bad?’

‘No,’ she said. ‘There were no serious mistakes. But there were other possibilities which would have made the story more interesting. An adviser would have been able to suggest them.’

I said: ‘Whatever’s wrong with the novel is my responsibility, and if I left out anything like that it was my fault. But I did have a consultant.’

I then told her about Spoder, who had advised me ever since I wrote my second novel.

‘I don’t think I know him,’ Frejah said. ‘Which force was he with?’

‘Salay Raba Police. He retired a few years ago.’

‘I never knew the Raba force well. What’s his full name, and what rank was he?’

‘He has never told me his given name – I don’t know why. I know him only as Spoder. He was a Detective Inspector before he retired. I don’t collaborate with him. I pay him a retainer, and on my behalf he browses for old files, cold cases, newspaper cuttings and so on. He leaves the stuff with me, and then I write the novel. If I miss anything, that’s my mistake not his.’