You know, I'm sitting here, trying to make the toughest choice I've ever had to make and all I'm thinking about is what the Master did. But that's not fair. There are so many things I haven't told you about. The time the Doctor left me stuck in the TARDIS – in a swamp! Hallowe'en in America. The giant mental birds and the sabre-toothed tigers and the badger-faced pirates. And, I really must tell you about the time we met the Terrible Zodin!

But that was back before everything went wrong. There was this time, ages ago now – before Saxon – where we went on this quest. We landed on a spaceship far into the future. But it wasn't like the Pentallian. It was like the ship had been grown rather than built. It was pretty amazing but, unfortunately, it was owned by this bloke called Baltazar. According to the Doctor he was the greatest despot who ever lived. But then, the Doctor says that about every despot. Anyway, this Baltazar wanted to get hold of something called the Infinite. It was another artefact from the Dark Time of Dark Space or whatever. And so, naturally, we had to stop him which meant going on this mad journey from planet to planet. We went to Pheros where there were these giant metal birds who ate gold. Then onto Bouken where we met some skeleton pirates who were attacking living oil rigs! Then to Myarr where these bugs were involved in a war with humans – all because of some dung. Then an ice planet called Volag-Noc where we trapped in this huge prison. And then onto the Hesperus Galaxy where we finally found the Infinite. It was wild, it really was. We saw so much in such a short space of time and I loved it.

And it wasn't just me. He was in his element. This was still quite early on though so I still wasn't sure what he was. I remember calling him a boy racer because in so many ways that's what he is but then I also saw him destroy Baltazar's ship with a spoon. I watched him stop a war in the space of a minute. He saved hundreds, thousands of lives without even blinking. He escaped from a high-security prison in less that five minutes. No wonder I felt the way I did.

Because that was when I really realised how I felt about him. The Infinite was this thing that could give you your heart's desire. So what did it give me? The Doctor. Well, a fake Doctor but yeah, it knew what I only knew deep down.

I love him and that's what makes this all so hard.

It tried to give the Doctor his heart's desire as well. At the time, the only thing I reckoned he'd really want is to be reunited with Rose. But looking back... knowing what I know now, I think that eventually his heart's desire did come true. He didn't want to be the last of the Time Lords. If just one other had survived, then he'd have some hope. Ironic, eh?

But back then, it was fun. Just seeing all those places and meeting all those people. Giant bug queens and robots and a man who was like a toad. And, yeah, saving the Earth with just a spoon. They were good times. So mad and mind-blowing and everything... and then we ended up here.

Me sitting here. Wishing it was like that again. But, after everything I've seen. After everything I've lost…

And all because of the Doctor's heart's desire.