Doom

I'm sitting in the doctor's examination room with my trousers off. Her neat, careful fingers are probing the soft area around my kneecap.

I watch her, and think: "Please tell me what to do."

She straightens up and says: "Well, I can't tell you what to do."

Then she says: "I don't think you'll be able to make it round."

Then she sees the look on my face and says: "You could start it, and just do a bit."

Then she looks at me again and says: "Or you could walk it."

I am struggling not to cry. I am struggling to replace my 'oh fuck' face with something blander and more grown-up. I can tell by the way my GP is looking at me that I am failing miserably.

For the last fourteen weeks I have thought of nothing but running this marathon. For the last three weeks I have thought about nothing but whether I can run this marathon after all. I have obsessed, every moment of every day, about how much my knee or my back is hurting me and what this means for my prospects of running.

My injuries have taken it in turns to torment me. For days, nothing. Then - a dull, nagging throb. Then - bam, a zinging trail of pain all the way up the side of my leg, or across my back. For a while, I couldn't figure out which was worse. Right now, my back is quiet while my knee, sparking and pulsing, makes stairs and hills an uncomfortable forecast of what awaits if I attempt to put it through 26.2 miles in six day's time.

Six days. I've trained for 14 weeks and now with six days to go I have to go right back to the start and figure out whether I'm going to do this.

I ask my doctor: "What about a steroid injection? What about really strong painkillers and sports tape? Can you give me enough stuff just to make it around, and then I'll rest it?"

She looks at me, a wrinkle of doubt in her nose.

"I can give you very strong anti-inflammatories that will help. I can give you very strong painkillers that will stop the pain. The thing is, if we do that and you run on it, then you won't know how much you'll be damaging it. You might find that you can't run on it again afterwards."

I gape. "What - ever?"

"Well.. for some time," she answers.

I think about not running the marathon, and I feel sick.

I think about starting the marathon and running a few miles and having to abandon it, and I feel sick.

I think about starting the marathon and running a few miles and then walking the rest, for hours and hours, past all the crowds of people cheering and yelling everyone on, and feeling such a fraud and a loser, and I feel sick. I think about limping down Birdcage Walk seven hours after the start of the race, to see the crowds have melted away, and the litter blowing in the breeze, and I feel sick.

I take the prescription from my doctor and I walk home. As I walk I think about the huge amount of money that my friends and family have pledged for me, have promised in support of a wonderful charity, Ambitious about Autism. I think about the work they do, and I think about the amazing school they run. I think about the day I visited, as a new patron, and watched a little girl - outnumbered as ever by the number of boys with autism - in her class, quietly bending to a task with a smile as her worker sat beside her. I think about my own daughter, who doesn't get to decide that she can't have autism today, sorry. I walk and I think and I think.

By the time I get home I've decided.

I've got a place in one of the biggest and best races in the world. And I've got a vest that says I'm part of a team of people who are ambitious about making things better for children who have autism.

I'm going to start the race. I'm going to pass over the start line to say thank you to everyone who sponsored me, and to say, to my daughter, I'm with you. And then - we'll see what happens. Maybe luck will be on my side and I'll make it to the finish line. Maybe I'll have to go home after three miles. Either way, I'll have been part of it, in some way. It's enough.

My new training plan.

To support me, and support Ambitious about Autism's aim to help children with autism learn, thrive and achieve, please click here