Lady Pembury was inspired by some of the discussion surrounding the broadcast of “The Unicorn and The Wasp” on TV. Many people compared it with Black Orchid, the last Doctor Who story to be set in the 1920s, and which had been criticised a lot. One critic suggested that the next time The Doctor visited the 1920s he ought to try visiting the working classes of that time, and that’s probably not a bad idea. I might well do that. But in the meantime, this is a story set in an English country house.

I set the story in the 1910s rather than 20s, because I like the Edwardian/Georgian period better. It is the period that Upstairs Downstairs was set when it was one of the most popular programmes on British television – along with Doctor Who! I was able to pinpoint it in time with the coronation of George V. The charabanc ride was extremely avant garde for the time, but perfectly plausible.

The story of the lost souls hidden down in the old monastery crypt actually comes from a computer adventure game called Broken Sword which has a sequence in which the heroes have to break a curse on an old house in Spain. Eventually a secret room is revealed in which there are two very old, dusty skeletons of two children hidden there at the time of the inquisition. They died of hunger and thirst and were forgotten. Gruesome and tragic stuff for a computer game. Rather gruesome for a Doctor Who story, too, but I thought a variation on the theme would be perfect for this story.

Lady Pembury being able to see ghosts, of course, is very much the same as the plot of The Sixth Sense. No ‘rip off’ was intended. It really didn’t even occur to me until I had written half of the story. But then, of course, it was easy enough to acknowledge that by have The Doctor tell Stella that Lady Pembury ‘sees dead people’ and Stella immediately understanding the film reference.

The mirrors reflecting each other is something that used to fascinate me when I was young. I used to like to put two mirrors together and create the effect. A Terry Pratchett Discworld novel, Witches Abroad, has a bad witch who uses two mirrors to increase her power and is undone when the mirrors are broken. Good witches were told never to get between two mirrors as they sap your soul. The idea that young Time Lords might be told something similar was too good to pass up. That The Doctor as a youngster would see it as a lesser version of that Untempered Schism he was forced to look into, was my variation on the theme that Pratchett got such good mileage out of as well as pointing to the way into the hidden place where the lost souls were.