A couple of years ago, I was profoundly depressed, inching closer to suicide and utterly lost. So I started looking for something. I had no idea what it was, but I knew it was not God.

Alf and Tommy

In 2014 I was fortunate enough to be accepted onto the Faber Academy "Writing a Novel" course. It's an intensive, challenging six months which gave me a great deal to think about. The course presents an eye-opening way to approach writing. We're encouraged to think about point of view, narrator, dialogue and structure in a way you tend not to, when you just sit and write. It changed the way I think about all writing. And indeed reading, too.

During one session, we were asked to "kidnap a character". This meant finding an unsuspecting member of the public and imagining their story. Faber & Faber's offices are in Bloomsbury and so we were released into the wilds of central London to find someone to use for our writing. I found myself in the Hunterian Museum. It's bizarre, unnerving and utterly fascinating. Based on a collection of animal and human samples, it's ostensibly a surgical museum, but probably draws as many visitors intrigued by the skeleton of famous travelling "giants" and "dwarves" of the eighteenth century. Some people inevitably come for the twisted and deformed samples - stored in thousands of glass jars lining the walls.

I saw a man walking methodically around the museum, quietly studying every exhibit - reading the signs in detail, ignoring the video of brain tumour surgery (skull sawing and all) to read about a heart-lung machine. I watched him pause at an exhibition about the early days of plastic surgery - pioneered during the First World War, when the hideous shrapnel injuries were unprecedented. He was, I discovered as I left, chaperoning a group of young adults, although he didn't interact with them at all until they reached the shop.

We returned to Faber's offices and were given 30 minutes to write a story, imagining our character and something they had great affection for. With this (quite wide) brief in mind, here's what I wrote:

Alf and Tommy

I can never go straight there. It takes me a while to build up to it. The kids wonder why we keep coming back here, but they don't really mind. Let dad have his moment - we can run about laughing at the dissected penises. Peni? Penises.

The animals first, to ease myself in. You feel bad for the deformed rat foetus, but then what kind of life would it have had? Then past the syphilitic bones - dissolved basically. The sheep gut condom makes me a bit self-conscious, to be honest.

It's ridiculous that there are no other pictures of him. How can they all have been lost? I suppose my dad wasn't so bothered. Perhaps he saw the image of his father - face scarred and distorted, even as he grew old - and thought only of pain. There probably weren't very many pictures to begin with. He wasn't a shy man in life, but it's not hard to imagine that he avoided cameras. Who wants to feel like a sideshow freak, even if the picture was taken with love?

It always annoys me that he's in the bottom light box. I have to crouch so low to see in. It's not designed for people to look for long, I suppose. When I do put my eyes against the holes and see the first grainy, green-lit photo, I hope it's not him. I don't want him to be in there, staring out at the twin-skulled cat all day and night.

Turning the knob, I know the order well. Tommy, Derek, Wilf, Robert then him. I've given them names, you see. Maybe others come and do the same and give my grandfather a name too. Perhaps even the right one - Alf would be a reasonable guess.

I don't mind that so much of his face is missing in the picture. In my memory he is never less than whole and I can full in the gaps where his cheek and jaw were. He had no choice but to learn to smile with his eyes and he did it with such a forceful luminosity that it took my breath away every time I saw him. It felt like a special light had gone on, just for me.

I didn't tell him what was happening at school or why I so hated the endless terms. I'd told my dad and look where that got me. But with him, I was free. Free and safe. For anyone to leave half of his face on a Belgian field and be such a complete human being still staggered me. That he could give so much love when most men would be consumed with hatred made him all the more incredible.

So I crouched and I stared and I had the same quiet conversation as always. "Love you, Pappy." I turned the wheel to Tommy. "Sorry Tom." But Pappy had seen enough horror - at least I could protect him from any more. "Love you , Pappy."

Who's There?