One of the joys of writing contemporary crime fiction is the way the supposed rules of the genre have collapsed. A succession of bold and adventurous writers have opened our horizons as never before. And what that means is that writers have more opportunity to boldly go wherever their imagination takes them. The only requirement, I suspect, is not to be dull.

For me, being able to write in whatever voice, style or milieu I choose has been hugely liberating. It means that when I sit down to write a novel, I’m not constrained by any perceived limits, so I can tell whatever story is clamouring to be heard. I can go into the dark places with Tony Hill. I can explore the recent past and the shadows it casts over the present in a standalone. I can be frivolous or terrifying. It’s entirely up to me to find the right way to tell the stories in my head and my heart.

So when the idea for The Grave Tattoo leapt front and centre into my mind, although I was daunted by the prospect of the research I knew it would require, I was gripped  by excitement. I realised that whatever form the book assumed, it was going to take me to new places as a writer. The challenge of what’s different or difficult is one of the key elements that keeps me enthused about what I do.

Now, to answer the FAQ – where did I get my idea from?

The Crime Writers’ Association has several regional Chapters. A bit like Hell’s Angels without the bikes (except when Zoe Sharp is around, of course…). The Northern Chapter has acquired the tradition of an annual symposium, which is a posh word for a weekend break where we take over a small hotel somewhere scenic then eat and drink and socialise with our colleagues and their significant others. In order for this to be tax deductible, we invite a speaker to educate us in some aspect of our craft.

About ten years ago, we were in the Lake District and Reginald Hill had organised for us a talk on murder in the Lake District in the 18^th and 19^th century. The speaker began by talking about notable local inhabitants, and mentioned in passing that Fletcher Christian and William Wordsworth had been schoolmates at Hawkshead School. That tickled my interest – I would never have made a mental connection between the high priest of Romantic poetry and the leader of the mutiny on HMS Bounty.

Later, the speaker revealed that the Lake District had become a haven for fugitives from justice in the nineteenth century. Lots of space, no law enforcement to speak of – the perfect bolthole for all those bad people from cities like Manchester, Liverpool and Lancaster. He continued, ‘And of course, there was always a strong and persistent rumour that one of those fugitives was Fletcher Christian. That he didn’t die on Pitcairn – he came back to the Lakes, where he was sheltered by his friends and family till his death.’

Somewhere in my brain, the synapses crackled and I was lost.

It’s a testament to the individual nature of inspiration that of the twenty or so writers in the room, I was the only one fired up by the linking of a single fact and a single rumour. I knew there was a book there for me – I just didn’t know what sort of book or how it would take shape.

I knew there would be a mountain of research to conquer, but my imagination wasn’t prepared to wait until I had all the facts at my fingertips. Armed solely with my fact and my rumour, the first notion that crossed my mind was that if he had come home, Fletcher Christian would have wanted to put his side of the story. And who better to put it to than his old schoolmate and family friend, William Wordsworth, now a respected poet? Wordsworth couldn’t have ignored such a fabulous gift. He would have felt compelled to make poetry of it. But it would be poetry that he could never publish because to have done so would have been tantamount to admitting to harbouring a fugitive from justice. It was a fascinating idea, but to see whether it would fly, I had to find out a lot more about both men.

My sole knowledge of Christian was based on the Trevor Howard/Marlon Brando film Mutiny on the Bounty. Not the most comprehensive of sources. And although I had studied Wordsworth as an undergraduate, our method of scholarship had been to consider the life only when it impinged directly on the art. So I knew the version of himself that Wordsworth had presented through The Prelude but I couldn’t remember if I knew how accurate that was.

There was no escape. I was going to have to sit down and do some proper reading. Biographies. Diaries. Letters. Normally, I prefer the sort of research that involves tracking down a living being who possesses the expertise I need to plunder, then plying them with food and drink till I have all I need to know. That’s more or less how I came by the forensic details in the book, and it’s a lot more fun than ploughing through biographies of long-dead poets, no matter how well written.

There are a lot of biographies of Wordsworth. Most are hefty tomes of excellent scholarly research, loaded with fact and sturdy with conclusions that seem to make sense. Juliet Barker and Stephen Gill seemed to me the finest proponents of this reliable and intelligent approach.

But I did stumble across a couple of books whose theories seemed so outlandish that I felt reassured about the apparent craziness of my own idea. My favourite was the one in which Wordsworth, Coleridge and their circle were painted as the Burgess, Philby and Maclean of their day, spying for the French during the Napoleonic wars.

There were some surprises too — discovering, for example, that it was Wordsworth who suggested to Coleridge that he use the until-then blameless albatross as a metaphor for sin and guilt. And that the suggestion was made at around the time when he could easily have learnt from Fletcher’s brother Edward, the Wordsworth family lawyer, that the Bounty crewmen had shot and eaten albatross on their voyage.

Even more interesting was the small matter of Wordsworth’s French girlfriend and their illegitimate child — a minor detail that he overlooked in his autobiographical verse and letters. As a young man, he’d gone to France at the time of the revolution, and while he was there, he fathered a child on a local girl. He planned to marry her but the Napoleonic War intervened and he had to flee back to England. The war lasted for fifteen years, by which time Wordsworth had married and started a second family. But the secret of his love child was kept hidden by his family. It would have stayed hidden if not for a couple of academic detectives who unearthed letters intercepted by the French censors which had sat disregarded in a drawer for a hundred and thirty years.

If the voluble Wordsworth clan could keep one momentous secret, I reasoned, they could surely keep another.

When it comes to Fletcher Christian and the aftermath of the Bounty mutiny there is little of an authoritative nature. The accounts we have were all given long after the events and they bristle with as many inconsistencies and improbabilities as there are wild theories to stitch them together.

But there are several suggestive things that we do know. We know that there is no grave on Pitcairn for Christian, the man who led the mutiny, founded the colony there and was a much loved and respected leader. Lesser figures have memorials, but not him. We also know that reports of his return to the land of his birth came from sources as diverse as a fellow officer on the Bounty and the poet Robert Southey. And there are lots of other intriguing facts, many of which appear in The Grave Tattoo.

In everything I read, I found nothing to contradict my beautiful, crazy idea. Gradually, I constructed a web of fiction built on the facts, a web that made sense of all the oddities. I didn’t alter anything that is part of the historical record. What I did was fill in the gaps.

There came a point where I had to test it out. That was when I was able to return to my normal method. Robert Woof, the director of the Wordsworth Trust, the curator of Dove Cottage and the Wordsworth Museum, and walking encyclopaedia on all things Wordsworthian, agreed to meet me. Hesitantly at first, then with more confidence, I outlined my idea and my research. He listened patiently, corrected me on a couple of details, then announced that he found the idea, though improbable, charmingly plausible. I felt as if a huge weight had been lifted from my shoulders. My only regret is that he died before the book was published.

I read far too many words in pursuit of this book. I fell into the trap, for a time, of allowing the research to become more important than the story. Finally, I amassed my arsenal of information and let my imagination loose, so that I could find a contemporary framework for my historical tale. I needed that because I had always known I didn’t want to write a history mystery.

At last, I was ready to roll. And the rest is, one might say, history…

The Grave Tattoo, Harper Collins pbk £6.99