Okay, so let's start with that killer question that every author dreads - where did you get the idea from for 'What If...?'?

Ah. That question... I honestly don't know. Usually there's a catalyst for the things I write about - an incident, a news item, a conversation, something unique that begs a question or conjures up a striking image - but the idea for 'What if…?' simply flashed into my mind one day from nowhere. A crude idea that is - the central characters; their basic makeup; what happens at the end - not the fully-fledged story. But for a long, long time I didn't have anything but these disjointed ideas. For years I kept going back to those, but nothing else came until I purposefully sat down to create the full story, then the ideas just wouldn't stop. I've a file of stuff I didn't use but the book's 109,000 words as it is, while, I believe, the average novel is only around 80,000, so it's a good job I left so much out. Like they say, always leave your audience wanting more, not wishing there was less!

How true. So when 'What if...?' stands up as a straightforward thriller, what drew you to all the weighty issues it covers - the environment, climate change, conservation, religion?

Simple - I wanted to really push the envelope. I mean, who hasn't dreamed of changing the world? Especially when they're young? We all think: 'just wait till the world gets a load of me!'. Unfortunately, most of us never even come close to making our mark and leaving behind a legacy, but it doesn't stop us wondering from time to time 'what if...?'. So I figured that would make a great story - feeling you're one of life's losers only to get one last chance to live the dream you've always believed you were meant to live. What do you do? Refuse the call and bury yourself in your miserable life? Or risk everything and grab your once-in-a-lifetime chance to achieve something extraordinary?

So it's about a little guy coming good?

It's an underdog story, yeah. The little guy sticking it to the Man.

Which the book does in reality, too, by highlighting many of today's global issues.

And one of the scariest aspects of writing, and I hope reading, the book is that everything it says about poverty and disease, about climate change and extinction levels, about human rights abuses, everything is 100% true. And that's real scary to me. It wasn't always easy finding entertaining angles to get this stuff over, but I was determined to do it.

You see, I love travelling and experiencing the wonders of the world, but sometimes it's heartbreaking to see what we're doing to the place. For example, in 2005 I spent two days cruising the Yangtze River, which is supposed to be one of China's most breathtaking journeys - mile upon mile or towering gorges with sheer cliff faces. Unfortunately, construction was underway to dam the river and had raised water levels so high those spectacular gorges have been reduced to little more than ordinary hills. Then, of course, there's the villages and millions of people the project has displaced, and the fact that the Yangtze River Dolphin has been pushed into extinction.

The problem is things like this are happening everywhere - people destroying everything without a care, no matter how irreplaceable. And all in the name of the almighty buck. It's criminal. But the strange thing is, if someone breaks into our homes to steal our treasured belongings, we're outraged and scream for a lynching. Yet so few of us raise so much as a finger to stop someone plundering the true treasures that lie just beyond our doorsteps. Now at least I can say I've raised a finger.

So you wrote the book to try to change people's attitudes?

It would be kind of naive to think my little book could do that. So no. Whether you want to call 'What if…?' a suspense thriller, mystery thriller, religious thriller, or eco-thriller, the primary word there is 'thriller'. If you clobber people over the head with a 'message', no matter how righteous your cause, they'll ignore you because they don't want to be preached to. The main reason I wrote 'What If…?' is that I believed it was a terrific story.

So why include all the 'change the world' stuff?

Because the opportunity was there. To have ignored it would've been reprehensible. My book is never going to end poverty, or global warming, or bring some extinct species back to life, but no one who writes, or paints, or composes, or creates anything, does it for any reason other than to move people. So if my story not only entertains, but makes just one or two readers question things, that's great. After all, even if you're 99.9% sure you're going to fail, you still have to try, or what's it all for?

And that's why you gave the book the philosophical angle?

Well, yes and no. Early on, I realized there'd have to be a substantial philosophical angle or the main character just wouldn't ring true. So it came straight out of the character - as true character development must That realization dominoed into the complete ethos of the book.

But when the book's so full of twists, action, love, and intrigue was it a struggle to keep the philosophy under control so it didn't overpower everything else?

Oh, yeah. Big time. See, I want the book to be enjoyable to two very different kinds of readers: those who simply want to a cracking, page-turner of a thriller and those who want a deeper, more thought-provoking tale that reveals something of the world, of people. It was quite a balancing act reining in the philosophy for the first group, while tantalizing the second enough to keep them hooked. It was a long slog - 19 months, writing 6-12 hours a day, virtually every day - but I think I've pulled it off.

That's a lot of work. Was it a trial or a pleasure by the end?

Oh, a pleasure. Always. It's wonderful seeing characters come to life; sticking them in seemingly impossible predicaments and watching them claw their way out; watching them fall in love, die, laugh, cry. Apart from writing the book, I've revised it so much I must have read some parts 30 or 40 times, but there are still sections that touch me.

I suppose that's not surprising after spending thousands of hours watching those characters struggle against everything you could possibly throw at them.

Exactly.

Okay, so if you loved writing this book so much, despite the 19 months of 12-hour days, what's next? A sequel? A prequel? A movie?

A holiday!