Memento Mori… remembrance of death. Having introduced the national flower of Gallifrey a few stories back it fell neatly into place for this short and relatively uneventful story in which The Doctor accompanies Rose and Jackie to the cemetery to pay respects at Pete’s grave.

That was the ostensible reason for the visit to the cemetery. But The Doctor’s thoughts turned on his own remembrances. This story introduces a new element in his family history. It has never been mentioned in the official canon whether The Doctor has any siblings, but some of the unofficial literature puts the possibility of him having a brother. I compromised by giving him a half brother who he was estranged from for most of his life, and another cause of regret and guilt. His brother died in the destruction of Gallifrey and he never made his peace with him. And on top of that, as he explains in this story, he is not sure whether the destruction of his homeworld was his fault. There are a great many hints in the TV series that The Doctor WAS responsible, deliberately or accidentally, for the holocaust. The strongest was in the 2006 episode, Satan Pit, when the ‘beast’ called The Doctor “The killer of his own kind” -  an accusation that shook him. But nothing conclusive is likely ever to be revealed on TV. It stands to the writers of non-canon fiction to fill in the blanks. And theories abound. Some have him ordered by the Time Lords themselves to destroy the Daleks and Gallifrey together. Others have it as an accident, others a deliberate act of genocide on his own volition. The last is, I think, quite unlikely. The Doctor has proved himself incapable of genocide more than once. In Genesis of the Daleks he was unprepared to destroy even THAT race. In Parting of the Ways he could not finish his own task of launching the Delta Wave. It seems unlikely that in between those events he would have done anything so out of character.