What made you want to become an author?
I've always loved reading and I've always loved making up stories. When I was little I used to write plays and force my brother and sister and friends to be in them (I'd always give myself the starring role of course!). But it never occurred to me that I could actually be an author as a job.
At school I enjoyed both sciences and languages and so when I had an opportunity to do a PhD in psycholinguistics – which is the study of how our amazing brains allow us to read, write, speak and understand language – it was perfect for me. I worked as a scientist for many years. It was a job I loved but I always had a secret ambition to write fiction. When you are a scientist you actually do a lot of writing – all your experiments have to be written up into papers and books – but there is one problem: you have to stick to the truth. Inventing stuff to liven the story up a bit is a major no-no! I feel very lucky to have had two of the best jobs on the planet – scientist and author. Now I just have mountaineer, tree surgeon and astronaut on my list!
How much money do you get being an author?
Like most authors I earn a small amount every time one of my books is sold. All those small amounts add up to enough to keep me in all the essentials for writing: notebooks, tea and an endless supply of biscuits. You never know, if gazillions of people rush out and buy my books I might be able to upgrade to gold-plated Jammie Dodgers one day.
Did you get any ideas from other authors to help you write the books?
I think that every book I've read has contributed something to how I write. Most of the time it's not a conscious process; the information just seeps in to my brain and mixes with the other ideas in there. It might just be a turn of phrase or a way of expressing a feeling or building suspense. But sometimes when I'm reading a crime novel, I'll come across a really great idea for a clue and I'll squirrel it away and see if there is a way I can adapt it to use in one of my mysteries.
For example, in one book I read years ago (I can't remember who it was by!) the investigator figures out that a car has been buried in a certain place in the middle of nowhere because the flowers of the hydrangea plant are coming up blue instead of pink in that patch – something that happens when the soil is more acidic; the acid was coming from the car battery. I've still not managed to work a version of that clue in to one of my books yet, but I will one day!
How did you think of your characters and who is your favourite?
Characters mostly just turn up in my head. They usually include a hotchpotch of bits and pieces of different people I know. Jack and Scott have a lot of elements of my two teenage sons – although I've mixed them up to create two new boys. Emily is really the girl I wanted to be when I was younger (except I was nowhere near as clever or brave as Emily).
One of the things I find it hardest to do is describe people's faces. I think it's related to the fact that I'm hopeless at recognizing people I don't know well – I'm always introducing myself to someone and then they tell me their name and I realize I've met them several times before (very embarrassing!)
To help me improve, whenever I'm in a crowd or on a train I study people and imagine how I would describe them in writing if they were a character. I'm sure it's very off-putting for my poor victims who must wonder why I'm staring at them and muttering under my breath.
I like to make sure that even the minor characters have some hidden depths as well as the obvious things that we see straight away. One of the best things about writing a long series is that I can come back to characters, who might only have a small part when they first appear, and build on their character to give them a starring role in a later book.
My favourite character has to be Mrs Loveday. She's so nosy and grumpy and I love thinking up her malapropisms (getting words in a muddle) like "windmill of opportunity" instead of "window of opportunity" and "criminal underwear' instead of "criminal underworld."
Are you going to write any more Adventure Island books?
There are no plans for any more Adventure Island books at the moment. Fourteen crimes is quite a lot for a small island, and Jack, Scott and Emily need to concentrate on their schoolwork for a while. But I'm definitely not saying never! Their adventures are such fun to write I'd be happy to return to Castle Key one day.
Did you base Castle Key and the area around it on a real place?
Castle Key is a fictional island. It's not on the map but if it were, it would be just off the coast, near Penzance in Cornwall. My sister and her family lived in Cornwall for many years and I loved going there to visit. It might have had something to do with my memories of reading Enid Blyton's Famous Five, as well as the romance of myths about Tintagel and King Arthur, but I've always thought of Cornwall as a magical place of possibility and adventure – which of course it is.
Do you find it hard to decide what the mystery is going to be?
With the Adventure Island books coming up with new mysteries got trickier as the series went on, as I didn't want to repeat anything too similar to the plots of the earlier books. Thinking of shady shenanigans and dodgy dealings that make an exciting and mysterious story, but are not too gory or unpleasant for younger readers is always a challenge, but it is fun too.
I'm always on the lookout for new potential crimes and make a note when I hear something that might work on the radio or TV (or even eavesdropping on other people's conversations on the train or in a café – a very bad habit!). I also get ideas from talking to my husband. He is a computer scientist but he is also worryingly good at imagining what baddies could be getting up to, and also my editor, who always has great ideas too.
Have you written any books that aren't about mysteries?
Good question! When I first started to write books for children I worked on a series called Superstar High, under the name Isabella Cass. It's about three girls who meet at an amazing boarding school for performing arts in London and become best friends. The books are mainly about the girls' ups and downs as they pursue their dreams, but I did manage to smuggle some mysteries in. For example, in the first book the friends have to figure out who is sending them songs anonymously for their band to perform in the talent show. I just can't resist testing readers' brains with a bit of detective work! Have you wanted to solve mysteries like in your books in real life?
Absolutely! I was always on the hunt for clues when I was younger. I desperately wanted to solve mysteries and catch criminals, just like The Five Find-Outers or Scooby and the gang.
I longed to find some suspicious footprints, a coded message or a secret passage that would lead me to hidden treasure. Unfortunately, the criminals in my area were useless; they never left any decent clues for me to find and they didn't even bother to signal to each other in Morse code using mirrors. So I had to make do with reading about mysteries instead. So you can imagine how much fun it is to be able to write my own mysteries now and make my baddies behave themselves properly!
How is the new series Secret of the Tombs different from Adventure Island?
The Secrets of the Tombs series has a lot in common with Adventure Island; it's all about ordinary kids solving mysteries, using nothing but their own initiative, reasoning and bravery. At their heart, the books are all about friendship, teamwork and striving to the do the right thing, even when it means putting yourself in danger.
The main difference is that the Secrets of the Tombs books are set in real-life locations around the world where there are hugely important archaeological sites. Book One, The Phoenix Code, is set in the Valley of the Kings in Egypt – the necropolis of New Kingdom pharaohs, including Tutankhamen and Rameses I.
The young detectives in Secrets of the Tombs are a little older than the team in Adventure Island. Logical, super-smart Cleo McNeil is 14. Easy-going, artistic Ryan Flint is 15. They are thrown together when an ancient relic, the Benben Stone goes missing from the recently discovered tomb of the mysterious Pharaoh Smenkhkare. It seems that a sinister occult group are trying to get their hands on the Stone. But then Ryan and Cleo discover the coded notes and journals of a young priest sent to investigate the whereabouts of the Stone over three thousand years ago, and they discover that the mystery is more ancient, more complicated and much more shocking than anyone could ever have suspected!
I hope that Adventure Island readers will enjoy all the mystery and adventure of Secrets of the Tombs. The new books are longer and the plots are a bit more complex, so they are suitable for slightly older readers. However, there's nothing to stop younger readers who like to get their teeth into a good, long story enjoying them too; there's still plenty of clue-busting, code-breaking and narrow escapes.
Why did you want to write about Ancient Egypt?
I've always been fascinated by the Ancient Egypt civilization, ever since learning about it at school. I think what also makes it so captivating is that so many written records have survived so we know such a lot about the lives of individual characters.
Did you have to do loads of research to write The Phoenix Code?
Yes, I read lots and lots of books and websites about Egypt and also visited great museums like The British Museum in London. I also went to Egypt and spent a week on a boat on the Nile. Each morning we would go on expeditions to look around tombs and temples. It was incredible! I just couldn't believe how perfectly preserved the paintings and carvings were. There was so much to look at it was impossible to take everything in; the Karnak temple complex, in particular, was just spellbinding. On top of the history, I also loved the beautiful surroundings of the Nile, especially the wildlife. There were birds everywhere! Every afternoon I spent hours scribbling down details in my notebook that I could use in The Phoenix Code.
Does the Benben stone really exist or something similar or did you make it up!
The Benben Stone is real in the sense that it features in Ancient Egyptian creation myths. It was a pyramid-shaped mound of rock that emerged from the primordial ocean at the beginning of time. In the legend, the bennu bird – an Ancient Egyptian version of the phoenix – lands on the Benben Stone and lets out a cry of "what will be and what will not be". The Benben Stone was housed in a special temple in the city of Heliopolis – which now lies beneath a suburb of Cairo. Nobody knows what happened to the Stone – if it really existed – but there are all sorts of myths and theories about where it came from (some people have even suggested it could have been an alien spaceship!) and the untold powers that it might possess.
• You can buy The Phoenix Code from the Guardian bookshop
