100 Sidney Street

100 Sidney Street was a large house in Stepney which was home to the Martian Embassy to the British Empire. It was decorated like a traditional Martian building: lacking any straight lines, carefully curved wall corners, and red-tinged lighting. The stools were three-legged.

Tom and Sherlock Holmes visited the Martian Embassy to discuss The Book of the Enemy with a Martian ambassador who was visiting Earth on a mission. Together, Tom and the ambassador went up a lift to the roof and looked through a telescope at Mars, the canals of which had disappeared. Holmes suspected this was because history was being changed in the War in Heaven.

When Tom read The Times the next morning, he found a story about a seige and gunfight between Russian anarchists and the British police, resulting in army intervention and the burning down of 100 Sidney Street. In attendance was Winston Churchill, the Home Secretary. This was said to have happened while Tom was in the building the night prior. The Martians, their invasion, and its aftermath had been excised from history and turned into fiction as H.G. Wells' The War of the Worlds. Holmes suggested that the seige and resultant destruction of the former Embassy was a greater power "cauterising the wound in reality" caused by the timeline shift. (PROSE: The Book of the Enemy)

Behind the scenes

 * In the real world, the occurred on 3 January 1911.
 * The siege of Sidney Street had previously been connected to Sherlock Holmes in 's essay Studies in the Literature of Sherlock Holmes, which compared it to the Holmes novel  and notably first applied the idea of "canon" to works of fiction.