The Doctor, as "James McCrimmon," claims to have studied at the University of Edinburgh under Dr. Bell. Dr. Joseph Bell was a lecturer and expert in observational deduction. He served as a mentor of Arthur Conan Doyle, who used Bell as a model for Sherlock Holmes.
Torchwood Reference: The estate on which Sir Robert lives is called Torchwood. After the events take place, Queen Victoria vows that to honor the acts of Sir Robert, she would found an institute dedicated to finding such strange events. She would name it The Torchwood Institute
In the original series' second season episode "The Crusade", William Hartnell's Doctor wistfully comments "I almost wish I was knighted too" after seeing Ian Chesterton being dubbed Sir Ian by Richard Lionhart himself. To that Vicky replies: 'That'll be the day!'; and so indeed, this episode marks the day.
Michelle Duncan and Jamie Sives were unable to attend the readthrough for this story, and their parts were read by David Tennant's parents, who happened to be visiting the Doctor Who set at the time. Tennant told reporters at the series' press launch, "Because it's set in Scotland they were delighted to be asked to read in. My Mum played Lady Isobel and my Dad played Captain Reynolds, and they were in seventh heaven. And they were genuinely cheesed off when they didn't get asked to play the parts for real! I was like 'chill-out Mum and Dad, back in your box!'"
At one point, Russell T. Davies contemplated surprising the viewers by having the werewolf kill Queen Victoria. This would then be the event which would cause the creation of the parallel universe to which the TARDIS would be drawn in the pivotal "Rise Of The Cybermen" / "The Age Of Steel" later in the season. However, Davies became concerned that this ongoing storyline would be too difficult for casual viewers to follow, and decided to drop the idea.
The Doctor passes himself off as Doctor James McCrimmon from the township of Balamory. Jamie McCrimmon was a companion of the second Doctor (Patrick Troughton). Balamory is a fictional Scottish village where the popular children's television series Balamory (2002) is set.
At one point Sir Robert, played by Derek Riddell offers to go out of the window and help Queen Victoria down. She replies that he is like her very own Sir Walter Raleigh. Derek Riddell had recently played Sir Walter Raleigh in The Virgin Queen (2005).
Russell T. Davies initially planned for the Doctor to give his name to Queen Victoria as a Scottish equivalent of his usual "John Smith" alias. He had difficulty finding something suitable, however, and quickly came up with idea of using the pseudonym James Robert McCrimmon.
The Doctor jokes about taking Rose to meet the Elephant Man. Merrick was famously played in the film The Elephant Man (1980) by John Hurt, who would later play the War Doctor. David Tennant returned for that episode as well.
Queen Victoria was not a hemophiliac, although she was a carrier, as were several of her daughters. One of her son's, Prince Leopold was a hemophiliac and died from bleeding on the brain after a fall. Because of the way the genetic disorder works. the victims are almost always male, the carriers female.
The werewolf in this story is computer-generated. Pauline Collins stated in a BBC press release that there were two performance artists who demonstrated the movements that the werewolf would do and talked about the problems of overacting in a situation where one was simply reacting to a green screen.
Script editor Simon Winstone has said that mistletoe is not indigenous to Scotland, and therefore its heavy presence in this story is supposed to further alert knowledgeable viewers that Sir Robert's father had deliberately imported it as a defence against the wolf.