CRIME fiction is a broad church. So too are most book festivals.

Other than finding their books vaguely in the same section of the shop, there would be little to link Christopher Brookmyre and Anne Perry, the former satirical, cynical and evangelical in his atheism, liberally and regularly sprinkling his books with blood, body parts and sweary words, while the latter looks back to a different age where decorum was prized and whose strong moral outlook in her book is coloured by her Mormon faith and themes of redemption which have deep personal resonance.

It would be hard to image such two different crime writers sharing the same stage, which is perhaps why Inverness Book Festival director Jason Rose arranged their appearances three days apart.

First up was Brookmyre, once, briefly, a resident of Inverness a few years ago, but for his latest book, "A Tale Etched in Blood and Hard Black Pencil", he was looking back even further to his primary school days in the West of Scotland, sowing the seeds of a present day murder mystery in the childhood experiences of a gang of pupils at a Catholic school, experiences which, however outlandish, are drawn closely from his own memories.

"I made a point with this book that I was going to use just about exclusively real events from my school days," he revealed. "Most of the characters aren't based on real people, but the events really happened and some of the events that might seem grossly exaggerated actually happened."

Not all the characters are entirely fictional. Mad Momo Monahan, the insane head teacher, is a character almost too extreme to be invented, a point picked up by Brookmyre's publisher who was careful to check the model for Momo was in no position to sue.

Brookmyre assured him his former heidie was no more, but added: "Even if the headmaster had been alive, I would have said: 'Bring it on' because I could bring 500 witnesses to say that was exactly how he behaved. He was someone who, in this day and age, would not have been allowed anywhere near children."

By using real incidents, Brookmyre said he was free to concentrate on the characters and bringing an adult perspective to his fellow pupils let him understand why the class pyscho was so dangerous or why such a person had bad hygiene.

It also gave him a chance to explore the language as well as the politics of the playground.

"There's a real vibrancy about playground language. Children don't hold back and they don't always understand the words they are using," he explained.

This use of playground language and West Coast slang resulted in the addition of a glossary which Brookmyre's publisher had originally intended for its website, but is now a hilarious appendix to his novel, though as Brookmyre pointed out, his perverse sense of humour means the definitions are equally as reliant on the reader understanding West Coast slang as the words themselves.

"One of the things I have found with this book is that people from all over the world say how much it reflected their own school life. My agent, who went to a posh school in the south of England, said it was the most accurate evocation of his own school days he had ever read," Brookmyre added.

As an author noted for such distinctive, if unwieldy, titles as "A Big Boy Did It and Ran Away" and "All Fun and Games Until Someone Loses An Eye", Brookmyre confirmed that it is often the title that is the starting point for his writing, "With this book I had the idea that I wanted to write this crime book that would go all the way back to primary school," he said. "I came up with a title I wasn't allowed to use, which was 'Peter Pan Got Shot Down Over Paisley', because the title Peter Pan is still copyrighted. But I had come up with a tagline for the book, which was 'A Tale Etched in Blood and Had Black Pencil', which the publishers actually liked better."

An earlier, less successful, tagline was "Terrorism is the new rock and roll", Brookmyre revealed. This was printed on the covers of "A Big Boy Did It and Ran Away", but three weeks before publication the Twin Towers were attacked, prompting a hasty redesign.

With questions open to the audience, your SHOTS correspondent wanted to know how Brookmyre felt when he heard that Harrods' boss Mohammed Al Fayed wanted to convert a disused oil rig on the Cromarty Firth into a luxury hotel. Exactly the same facility in the same location as the one taken over by terrorists in Brookmyre's fourth novel, "One Fine Day in the Middle of the Night".

"Jubilant," was Brookmyre's response. "Remembering how it ended for Gavin Livingstone in the book, I couldn't wish him any more success. I hope it has much the same ending. With him still in it. I came up with that idea as sort of a satire on insular British tourism; that people want to go abroad without actually going abroad. But beyond that I wanted to come up with the worst idea in tourism ever. And it turned out he thought it was great idea and he wants to give it a test!"

Others wanted to know his view of the recent TV adaption of the first Brookmyre novel, "Quite Ugly One Morning", with Irishman James Nesbitt in the role of Scottish hack Jack Parlabane, Brookmyre's main recurrent character. The author's response was largely positive, aside from his disappointment that so little of the dialogue from what was a very dialogue driven book had been used. However, Nesbitt has been quoted as saying it is the best thing he has done and with good ratings, another Parlabane tale should make it to the screen.

If it does, Brookmyre would like to see his favourite Parlabane book filmed. That is his current work in progress, still a couple of days away from completion while he was in Inverness, "Attack of the Unsinkable Rubber Ducks", which sees Parlabane debunking psychics, mediums and other assorted phenomena.

"I've been trying to come up with a word for all that and I can't come up with a better description than 'Bollocks!'" the sceptical Brookmyre added.

There was another reason why he was so keen so see the new book filmed. The production company which holds the screen rights to Parlabane, and has commissioned a horror film script from Brookmyre, has enjoyed considerable success with ITV drama series "Afterlife" - about a medium who can't stop seeing ghosts. "I would just find that so funny," Brookmyre laughed.

There were less laughs, swear words, and indeed people, at the Anne Perry event a few days later, though the latter can be attributed in part to the lunchtime scheduling.

Ms Perry's conversation was bright and enthusiastic, concentrating on her writing life and her status as a long time Highland resident, living up the coast at the pretty Easter Ross village of Portmahomack.

"People ask me: 'What do you want to live there for?' Well, one thing I know when they ask that, they've never been there," she said.

Living in the Highlands does not mean she has to stay in the Highlands. As a successful author with 20 million books in print in nine languages invitations come steadily and though Inverness is the only one she can drive to in time for lunch, others in her itinerary this year include Canada, Texas, Brittany and Italy.

"If you don't accept the really fun invitations you might not get asked again," she said.

She later revealed that this hectic schedule does not interfere with her writing. Ms Perry writes the old fashioned way with a pen and paper, so much of her writing is done in airports and hotel rooms, while travelling to new places and meeting new people is so exhilarating she returns to Portmahomack energised from each trip.

It seems to work. Her prolific output now runs to about 50 books, including a two book fantasy series drawing on her Mormon faith and a novel set at the time of the French Revolution "The One Thing More", but the bulk of her fiction comprises three historical detective series. She did give a hint that she is planning a move to a new location and different century in a forthcoming book, though she firmly ruled out any flirtation with more contemporary crime.

"There are lots of interesting people in the market. I've got this niche, historical mysteries, and I'm sure if I presented my publisher or my agent with a contemporary crime novel I'd be told: 'We've got 100 people doing that very, very well already," we don't need you.

Her first series details the adventures of policeman Thomas Pitt and his upper class wife Charlotte in late Victorian London, her second is set a few decades earlier in the 1850s and features Monk, a former policeman who becomes a private investigator after an accident robs him of his memory.

Her most recent series is a quintet of novels set around World War One with the central character a front line chaplain Joseph Reavley, based on and named after Ms Perry's own grandfather, himself a World War One chaplain.

"I have done 15 Monks and 25 Pitts, give or take, and while I still enjoy them, you have got to keep stretching," she said. "What I think is interesting about writing mystery stories is that the pressure of investigating and discovering what your own values are is what makes it a story. How well do you really love. How well do you really know yourself. Sometimes you don't know yourself as much as you thought. Some things will happen and you will find you are much more frightened, much more undecided than you thought you were going to be. Sometimes you find you have much more courage and generosity than you thought."

This was the great attraction of setting a series in the period between June 1914 and November 1918, a period Ms Perry suggested marked the end of history and the beginning of the modern world, resulting in the decimation of a generation and great social and political change.

Such extremes forced characters to question what they really believed and what they would die for.

"When you ask these questions you get right down to the bone," Ms Perry said.

Writing about such experiences also took the author to the edge of the abyss and she had to draw on her own experiences to share what her characters were feeling, experiences she also drew on while recreating the past.

"We all know what it's like to be cold and wet and so tired you are zooming in and out of consciousness even when you are standing up. We know what it's like to be hungry, even if it is only one day and you get some idea of what it was like. Not physically, but the emotions are there," she said.

She joked that she had not gone down into the London sewers, a setting for her latest Monk novel The Dark Assassin, and had just watched "The Third Man" instead, but she added that she also had a friend who had gone into the Paris sewers and described very well the sense of complete disorientation and utter darkness.

The conversation ranged over the inevitably in dealing with class in writing about Victorian England and why Superintendent Pitt, as he later became, is so well educated for a working class lad of his era.

"Pitt has a good education because he was educated with the son of the big house," Miss Perry explained. "The son of the big house was a bit lazy so they got the gamekeeper's son in so they could say: 'If you can't do better than the gamekeeper's son, what's the matter with you.' I wanted him to be intelligent and not really stuck with a poor education and the stigma that brings. But he has the compassion and the understanding I want for a man in that position.

"He wouldn't, honestly, have been a policeman in that time had he been a gentleman's son. He might have been Chief Constable, but I don't want the Chief Constable. I want the man who does the questioning, who finds the body and has the nasty job of speaking to the relatives and who's there."

As for plot, Ms Perry revealed that she writes a very long, detailed outline for each of her books, but in some cases became so fond of her original murderer that she had changed whodunit to allow them to get off.

She also offered up what she said was the she had to a successful formula, which was care about what you are writing.

"There are millions of books out there. What makes a reader pick yours off the shelf? It had better be because your heart is in it and your brain," she said.

Someone who once said no-one could pay her not to write, Ms Perry said she did not even take holidays. "I get taken all over the place as it is and to be taken away to do something is much more fun," she went on."I don't ever want to retire. I want to die with a pen in my hand. I never want to stop writing. I love it."