You said you'd come to say goodbye, that you were burning up a sun just to do it. I guess I should feel flattered; I know you didn't do that for everyone. Sarah-Jane never got her goodbye until recently, and I know you, you hate goodbyes. Maybe I'm the first one to ever get a farewell.

But you didn't say it. You never said goodbye. You hardly said anything. You stood on that beach, with just inches between us, but it might as well have been a universe. I guess it was. You told me I was dead, officially, and I think it was then I knew that what you were saying was true. I could never go back. A dead person cannot come back, you told me that. An ordinary person, the most powerful thing in the universe. Even without the Bad Wolf thing. If I returned something awful would happen. The universes would implode; they'd probably make that noise Jack made. You know, the one in Cardiff. I don't know, maybe you don't remember that anymore. Maybe you don't remember any of that anymore. For all I know, I could be saying all this to a man who isn't the man I left behind. You could have changed endless amounts of time since then and become someone altogether different. But I like to make believe that you haven't. I like to pretend that somewhere you are who I knew still…

I know I can't be with you anymore. I know it would be an impossibility for me to ever see you again, even for a moment. It would break all those Time Lordy codes of yours. But it doesn't stop me wanting it, it will never stop me wanting it. If you could see me now… I never stop thinking about you, you just won't leave me alone. I think about you when I wake up in the morning and when I go to sleep at night. All day at work and at home and wherever I go, you're there. I can imagine your response to every thing I say and do, to everything that happens in my newly mundane life. I know you so well that it's almost like having you here with me. Only you're not, and it hurts like hell.

At first I kept looking over my shoulder, forgetting for an instant that you wouldn't be there, that you couldn't be there. I'd find myself glancing over for someone to roll my eyes at when my mum or Mickey said something. You wouldn't believe how much that crushed me, those moments when I'd wonder where you were, like you'd just popped outside for a breath of fresh air. The instant panic. And then the realisation that you were never going to be there again. You'd think I'd have become used to that as the months have gone by. But I haven't, and I don't think I ever will.

Mum has promised me that in time I'll be able to look back on our time together without flinching. She says that time is a great healer, that one day it won't twist me inside out to think about you. She should know, I suppose, she's lived through a loss. A bereavement. That's what everyone calls it. It's an explanation, I suppose. It's not like anyone would believe the truth.

I sometimes wish you were dead. There, I've said it now. I don't mean I'd wish you a slow and painful death to get you back for abandoning me here. It wasn't your fault, and I mean that from the bottom of my heart. It wasn't your fault. I guess I should have perfected my grip years ago; all that gymnastics training didn't really pay off did it? So I don't mean I want you to suffer for it. I just mean it would be easier for me if you were dead. I'm sure I could get over that. But to know that you're out there still, living on without me, seeing things without me… It tears me apart. I want to be the one with you, I want you to show me things I've never seen before. I don't want this stupid life anymore, I want to be with you. Wherever you are.

And yet, at the end of a long day, when work's been awful, and Mum and Dad have been fighting because they're both so sleep-deprived since James was born, you're the one thing that keeps me sane. I can think about you and imagine where you are, and somehow, it all seems worth it. Because I did what I had to do; I saved you and the universe. Twice. And no one will ever know, but that doesn't matter. I just need to know you're okay, and you'll keep being okay. Because I worry about you.

I worry that you'll be lonely without me. You said travelling the universe was a lonely place if you didn't have a hand to hold. And I think about you, in that blue box of yours that Mum was always so suspicious of, and I worry that you've got no one's hand to hold anymore. I made a promise that I'd never leave you and I broke that. I made a promise to myself that you'd never be lonely again, that you'd never have to feel like you did when you first met me. I broke that one too.

I worry that you've got a new companion, a new hand to hold. And I worry that they don't understand you like I did and they don't hold your hand properly. That they don't stir your tea properly, that they don't get the crease in your trousers exactly down the middle. I worry that they don't smooth your hair down properly, or stop you from sitting on your glasses. I worry that they leave you alone for too long, absorbed in their own problems.

But I worry most of all that they do all those things to perfection, ten times better than I ever did, and that you can't help thinking that you've got a better deal this time around. That you rarely think of me, and that if anyone asks you about the girl you had before you say, " Oh yes, erm… oh what was her name?" That I've become just another name on your long list of friends, acquaintances. That I don't matter anymore.

But whenever I get too deep into these thoughts, in the middle of the night, when my pillows sodden with tears and I have to bury my head in my duvet to stifle the sobs, I think one thing.

You didn't say goodbye. So maybe it's not over yet.