Asked at the very beginning of this panel session how she came to write the new Poirot novels, Sophie Hannah laughed. As a self-confessed Agatha Christie “super fan”, she told us, she’d never in her wildest dreams considered offering her services to the Christie family.

And yet, life can be stranger than fiction. One evening, Sophie received a call from her “brilliant but weird” agent, telling her that he’d just been to a meeting with Harper Collins during which he’d sat next to a shelf full of the legendary crime author’s books. An idea came into his head and he interrupted the meeting to tell his hosts that they should hire his client, Sophie Hannah, to write some Poirot novels. Strangely enough, his offer was rebuffed and the meeting continued (“I was mortified when he told me”, recalled Sophie, three years later).

However, a higher power must have been listening, because the very next day Sophie was informed that the Christie family would like to meet with her. “I thought they’d hit me with an injunction”, she joked, before recounting a tale of champagne, canapés and an eventual book deal. Matthew Pritchard, Agatha Christie’s grandson, had told Harper Collins that the family were, at last, ready to continue her legacy.

A “bullet-proof” contract followed, providing the Christie family (understandably) with lots of opt-out clauses – but they have, says Sophie, been a “dream” to work with, always supportive of her ideas and contributing constructive suggestions.

“I’m not pretending to be Agatha Christie – or to write like her”, Sophie stated. Instead, her aim is to write Christie-esque stories – and she has created a new narrator, Inspector Catchpool, who is a sidekick to Poirot in the way Hastings was, but who learns from his mistakes. We see his character develop through Sophie’s novels.

Of which there was only ever meant to be one – ‘The Monogram Murders’ – but it was such a success globally that the Christie family asked her to continue; ‘The Mystery of Three Quarters’ has just been published.

Lucy Foley, author of this year’s literary sensation ‘The Hunting Party’ and whose novel ‘The Invitation’ I referred to in my first Guildford post, is another Agatha Christie super fan and told us she is thrilled that her new book has been described as Christie-esque. It has an intriguing premise, being set on a remote estate in Scotland, which Lucy and her husband had visited and been told that, should the weather be inclement, they might not be able to leave (yikes). This setting, Lucy told us, informed the novel – and turned the direction of her writing.

‘The Hunting Party reunites a group of thirty-something university friends. Beginning with lots of drinking, over the course of several days dark & buried secrets rise to the surface and the gang begin to realise that they may not be as good friends as they thought. Then, a body appears.

“I wanted to explore the idea of groups of friends”, Lucy explained, “faced with an outsider”. Emma, the girlfriend of one of the characters, didn’t go to Cambridge, unlike the rest of the group, but has organised the gathering. Then you have Miranda, the glamorous party girl whose life isn’t going to plan – and Katie, a successful lawyer who resents the role her friends still expect her to play.

Both novels, commented our host Fanny Blake, are fantastically complex, with lots of twists and turns. What do their authors believe makes a good thriller? “Structure”, responded Sophie Hannah. “It might sound boring, but it’s what the reader needs to make a good story”.

Lucy Foley agreed, adding that hidden clues, which the reader only spots at the end of the book, are also important.

Does being a crime novelist make you better at solving other people’s mysteries? Definitely, according to Sophie, who claims she can spot any novel’s twist in its first chapter. This, she says, is awkward when she’s asked for dust jacket endorsements: “If I’ve guessed the answer early on, I won’t give one!”

We all love a clever twist or surprising resolution, so which are our two authors’ favourites? For Sophie Hannah it’s ‘Murder on the Orient Express’ (“It gave me a physical sense of shock”) and ‘Before I Go To Sleep’. For her part, Lucy Foley extolled the virtues of ‘And Then There Were None’. “It’s raw and dark…and completely watertight”. Describing it as her favourite crime thriller of all time, Lucy added that this novel proved that Agatha Christie wasn’t just a cosy crime writer. “Christie is brilliant at showing why “ordinary” people kill – and why we are all capable of murder”.

But can the need for a twist or a revelation come at the expense of your characters? “Only if it’s forced”, believes Lucy – and your characters need to be fully developed. Sophie concurred, adding that from an author’s perspective, this can take you down a wrong path. Just because one particular novel with a twist works well, doesn’t mean the same treatment should be applied to all thrillers.

Excitingly, ‘The Hunting Party’ is being developed for TV and will be filmed in the same location as ‘Top of the Lake’. But do crime novels, in general, translate well to film and TV? Both authors acknowledged that the process can go horribly wrong, but gave examples of successes, Sophie hailing the movie ‘Gone Girl’ as “amazing”. What’s important is for the director to identify what matters about the book and invest it in the screen version.

I was so inspired by these two authors and their evident passion both for writing and for books in general. Stay tuned for Post 3 from Readers’ Day, in which Erin Kelly and Marianne Kavanagh share their love of gothic melodramas with us.