When Mike Craven sent the draft of his novel The Botanist to a scientist friend, the response wasn’t quite what he had anticipated.

“He got straight back and told me I could face ten years in prison for revealing the recipe for ricin,” explains the Carlisle-born novelist with a wry smile. “Even searching for it on the internet is an offence under terrorism legislation, and I’d inadvertently included details of how to make it!”

The deadly toxin, derived from castor beans, plays an important part in Craven’s book, which won the prestigious Theakston Old Peculier Crime Novel of the Year award earlier this week at the Old Swan Hotel in Harrogate, North Yorkshire.

“The security services apparently are playing whack-a-mole when recipes crop up online. As soon as they’re up there, they take them down. And then another one crops up. And I just happened to come across one by chance,” he continues.

“It’s such a simple thing to make, you can buy everything you need off Amazon for about £200. But I didn’t know it was illegal so I just wrote it down because I thought it was interesting.

“My friend, Brian Price, who’s also an author, told me someone was going to go to prison under the Terrorism Act if we published it. If you’ve watched Breaking Bad, when they include the recipe for Methamphetamine crystal meth] they miss out some key processes, so you can’t watch the TV show and then make it. So I did the same. And I think I owe Brian a drink.”

The deadly poison is one of the tools used by Mike’s baddie, the so-called “Botanist” of the title, as they take out unpopular celebrity targets, to the delight of some.

The author, who writes under the name M W Craven, jokes today that his book, the fifth in his bestselling Washington Poe series which features the UK’s version of the FBI, is his most “woke” because the victims are such an unlikeable bunch.

They include corrupt politicians, hate-mongering social media influencers and a drugs baron who has bought a prescription medicine then jacked up the price (based on US hedge fund millionaire, Martin Shkreli, who faced a backlash after buying the manufacturing licence for the anti-parasitic drug Daraprim and raising its price by a staggering 5,455 per cent).

“Reviews have branded it a woke book. Though, incredibly, a few people have been siding with the victims,” he laughs.

“And I’m trying to think of which particular victim? Is it the woman who is keeping modern slaves, or the racist or the misogynist, or the corrupt MP… or all of those?”

Indeed, his outspoken DS, Poe, finds the victims deeply unpalatable even as he is trying to save their lives. Mike adds that the book is based on a series of so-called “locked room” mysteries, inspired by his friendly rivalry with Anglo-Asian novelist Abir Mukherjee.

Having been a regular at the Harrogate Festival, perhaps the world’s most famous celebration of crime writing, now in its 20th year, since 2011, Mike is delighted to have been chosen by judges for its top award, supported by the Daily and Sunday Express.

Simon Theakston of title sponsor Theakston Brewery presented the 55-year-old author with a hand-made beer barrel and a cheque for £3,000 at the ceremony on Thursday evening. Elly Griffiths was awarded a highly-commended for ther book, The Locked Room.

“I’ve been coming here as a reader, as a soon-to-be-published author and now as an award winner, so I feel like I’ve come full circle, it’s a real honour,” Mike explains. “My editor was buying champagne but I don’t like it, it just tastes like fizzy cider to me.”

Mike has enjoyed a storied life. Growing up in Newcastle, the son of a cigarette salesman and a nurse, he joined the Army on a whim, spending 12 years in the Royal Electrical and Mechanical Engineers, before studying social work at university.

From there, he joined the Probation Service and worked his way to the top in Cumbria where he eventually took redundancy as chief probation officer when the service was privatised. But it was a brush with death from a rare cancer 20 years ago at the age of 35 that changed his life and set him on the road to being a writer.

His Lake District-set series, featuring Poe and civilian crime analyst Tilly Bradshaw, who enjoys a genius-level IQ but lacks social awareness, set him on the path to success in 2018 with The Puppet Show.

The pair are unlikely allies who become firm friends in a fresh take on the classic police procedural. Mike’s latest book, Fearless, is an American-set standalone starring former US Marshal Ben Koenig, but he aims to return to the series next year with his “darkest book yet”, The Mercy Chair.

He tries to vary his books – citing US crime legend and former Harrogate special guest Michael Connelly as inspiration – so The Botanist was lighter in tone ahead of its forthcoming darker sequel.

“I hold Mike Connelly as the gold standard, whatever he writes, it’s different in tone to his previous book,” he says. “So because I knew the plot of The Mercy Chair was going to be incredibly dark – my agent couldn’t read it in one, he had to take a break from it – so I made The Botanist a lot lighter than I had originally intended.”

Mike adds that he enjoys the humour of previous Crime Novel of the Year winner Mick Herron’s Slough House books, adapted into an Apple+ TV series starring Gary Oldman. While he is reluctant to reveal spoilers for the next book, Mike does admit to refusing to kill off Poe’s love interest, pathologist Estelle Doyle, because he didn’t want his character to be too miserable. “Poe deserves to be happy for a while, so she’s not gonna die anytime soon,” he smiles.

There will also be a second Koenig book next year and Mike is currently involved in bringing Fearless to the small screen.

The rights to the Poe series have also been optioned for television set against the stunning backdrop of the Lake District.

Mike believes the rise in people holidaying in the UK as a result of the pandemic and more recent cost-of-living crisis means people feel a connection to the Lakes.

“Britons feel like collectively we own the Lake District because almost everyone has been. It’s a big national park, there’s beautiful scenery, and there are nice restaurants. It’s everything you want for a holiday,” he says. “That’s part of the success of the books, but also there’s a literary history with people like Beatrix Potter and Wordsworth. I set the first one, The Puppet Show, in the Lakes with the intention of moving around the country because Poe and Tilly work for The National Crime Agency’s serious crime analysis section, but my book contract was for a procedural series set in Cumbria.

“So now for every book, I’ve got to invent a reason for them to come back to Cumbria.”

Mike pays tribute to his wife Jo, who reads all his books early, and warns him if he’s gone over the top with any of his murders.

“Ideally I was to write 20 Poe novels and in 10 year’s time get a lifetime achievement award because I enjoyed writing these. It’s fun. I can go quite dark in my books, because I can always shock people out of the darkness with something sarcastic.

“The humour is a device for me. But it’s lovely to be writing the sort of books I like to read.”

• The Botanist by M W Craven (Constable, £9.99) is published and won the Theakston Old Peculier Crime Novel of the Year 2023. Visit expressbookshop.com or call 020 3176 3832. Free UK P&P on orders over £25.