In Dark Covenant, a novel published by Peter Luther in February, a disfigured prostitute from Victorian times finds her life transformed when she encounters a sinister newspaper known as “The Shilling”. She amasses a vast estate and great wealth, and her legacy is bequeathed through the ages, with The Shilling proving its metamorphic potential for each of those to whom it passes. Eventually, now in the form of a glossy magazine, it reaches Lewis, a solicitor based in Wales who is down on his luck.

Exposure to the magazine radically changes Lewis’s humdrum life. While before he struggled to find, let alone retain, clients, suddenly he becomes his firm’s leading fee-earner. The firm is saved from extinction thanks to Lewis’s conjuring of cash-cow cases, which itself flows from his ability to decipher crossword clues in the magazine. Each successfully decoded clue provides him with another form of enrichment. He glories in revenge on his tyrannical boss, sees his share-holdings rocket to the stratosphere and, bucking the trend of most lawyers’ lives, acquires mesmerising sex appeal.

The plot of Dark Covenant – which has become a word-of-mouth publishing sensation - reads as if it might have been conjured by a disgruntled trainee solicitor whose time-sheets were filled with literary scribblings rather than billable hours. And so – almost – it proves. Luther is a solicitor with Wales-practice Rausa Mumford. He is not, though, a lowly trainee but a partner who specialises in personal injury litigation and commercial work. Luther, who admits that he has always wanted to be a writer, strongly believes that writers should write about their own experience.

“I’m a great believer in writing what you know about, and this is true even of supernatural thrillers,” says Luther, 43. He says that Dark Covenant “is set in a solicitors’ office similar to my own,” and that, for a time at least, “the main character’s aspirations were my own”. Supernatural they might be, but Luther’s work – he has completed a second novel, Dead Letters, and is busy writing his third – derives much of its impact from its quotidian settings. As he explains:

“My stories aren’t set on some alien planet or alternative reality, or in some fictitious backwater a broken telephone line away from civilisation. Cardiff and Tenby are the principal locations for my first two books, and the characters are normal people with normal lives. I inject the supernatural content into the story in a logical fashion, provoking a realistic character response. I think I am only able to achieve this by believing in the outrageous concepts myself; I admit to becoming a faithful disciple of the twisted logic driving my plots.”

Luther cites C S Lewis’ The Screwtape Letters - he named the principal character of Dark Covenant after the author - as a major source of inspiration. He adds that the novel also has “more than an echo of The Picture of Dorian Gray, one of my favourite books - alongside everything written by Charles Dickens.” Doubtless what he describes as an upbringing in “an Evangelical church where hell and damnation are absolute certainties” also played a part.

Luther finds the time to write by being disciplined. “You have to make sacrifices if you want to write. You have to say ‘Right, I’m not going out tonight’ or ‘I’m getting up early.’ It’s got to be a passion that drives you. I haven’t got any time for would-be authors who say they haven’t got the time to write.”

Luther kept the faith throughout his 20s, when, by his own admission, he penned a series of books that were “a little less awful each time”. He abandoned writing at the age of 30 and threw himself, Lewis-like, into stocks and shares – only, unlike his protagonist, to lose a fair amount of money thanks to the market crash of the early 90s. “That made me think ‘what the hell have you been doing? Life’s not all about money, it’s about your passion.’ Mine had always been writing so I returned to it.”

Capitalism’s loss has proved to be supernatural fiction genre’s gain, as the unravelling of the Faustian pact in Dark Covenant has garnered both strong sales and oodles of feedback. But how close is the novel to Luther’s own experience?

“All the characters are fictional and none of them resemble any of my colleagues,” he replies. “But as lawyers there is always a line that you have to stop yourself from crossing. Temptation – to please the client, to take a short cut – can rear its head. It’s true to say that my understanding of this aspect of legal life was an inspiration for Dark Covenant.”

A warning to lawyers tempted to read Dark Covenant: you too might recognise aspects of your character.

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