John stared at me intently over the remnants of the Chinese takeaway. His ever-sad eyes were filled with confusion. I sipped my tea uncomfortably. He looked anxious about the ominous silence continuously resonating from my mouth.

Usually I'm a very talkative person - always forgetting who I really am:

I am a murderer.

Surely, I would have to tell him soon.

I hate being a liar.

I was, today, uncharacteristically silent. Today was my true birthday; thirty-nine, exactly today. Obviously, it wasn't what John thought. In his eyes, I wouldn't be thirty-nine for another six and a half months. I smiled inwardly. He had already told me about the nice romantic dinner he had planned for my fortieth - both he and I weren't one for parties, really. It's uncanny how much we have in common, even though he doesn't know it. Yet.

I must tell him soon. It's unfair on him.

I could tell he still ached from Sherlock's suicide seven months ago.

No, not yet; I couldn't tell him. I couldn't pain him even more.

Anyway, my birthday reminded me of my true identity. An identity I must reveal to John. Soon. He needs to know who I really am; otherwise it would be too unfair on him.

But I couldn't pain him even more. He is the only person I have loved in my whole life. He loves the false me. He would hate the real me. I still didn't say a word; I didn't look at him. I just swirled my tea in my favourite red spotty mug; the quiet ''slosh'' the only thing breaking the silence.

''Mary?'' He finally enquired. ''Is anything wrong?''

''Yes,'' I replied cheekily, ''your moustache is not very spectacular yet, is it?''

He stroked the coarse, blonde-grey ghost of facial hair hovering above his upper lip.

''Whatever.'' He smiled. ''It will be less immature soon.''

Oh God, I loved him so much. It kills me a little every day, knowing that this relationship is only a lie. But here I was, lying. The truth would be almost as bad as Sherlock's death to him. It may push him to breaking point and I don't want to see that. Not my John.

Damn, I will tell him. But not in person. I'm too much of a coward to do that. I shall type it up and put it on a memory stick. By the time he reads it, I will be long gone.

It breaks my heart to know that this day will come soon.

Okay, so I have decided to write this in a letter format. It feels more personal, and when you read this, John, it will feel like I'm talking to you. Even though you will hate me, at least we may be able to keep this part-contact. You will remember me as a person (a false person at that) and at least you will not remember me as sheets upon sheets of endless non –emotive robotic data.

I know you will never see me again when you read this. I will be far away; far away from this country and this pleasure of a life that I never deserved.

I never deserved you, John, and you deserve so much better than me. You are the best man I have ever known, and I owe you so much. So much that you will never have to ever look at this lying, cowardly, wretched face again. It aches with longing, regret and bittersweet sadness for your sake.

And this ache will continue forever.

Your Mary Morsden will always exist in the depths of my soul, no matter what false identity I choose next, whatever hatred you will feel for me - I will never stop loving you.

This memory stick will be all you have left of me. Please read it, you have a right to know who I really am.

I pause.

I gulp. A single, warm tear forms in my right eye. I brush it away impatiently, not caring about my already smudged mascara. There are much more important things in life than looking good for somebody who won't love you for much longer.

I breathe in and continue typing.