So where is Cato Street? In short, it’s a mews-alley , just behind the Edgware Road, not that far from Oxford Street. It was first erected around 1803 as a gentleman’s stable and coach-house, and it stood in an unpaved lane of cottages for labourers. In late 1819 the stable belonged to an Indian army officer, General Watson, and was let to conspirator John Harrison because of its proximity to their intended target. This was Lord Harrowby’s house at 44, Grosvenor Square. Harrison, a former Life Guard, who had been based at the nearby King Street cavalry barracks, said he wanted to keep his horse and cart there. In truth, he was really looking for somewhere for himself and his friends to meet before they ventured forth in hope of changing the course of history. One conspirator, the Jamaican William Davidson, had once worked for Harrowby as a cabinet maker on his country estate. Now he was hoping to put Harrowby in a different kind of wooden box. To succeed on their mission the conspirators would need to neutralise the threat posed not only by the cavalry barracks at King Street, but by the Foot Guard’s barracks in Portman Square. They were hoping many of the soldiers would be in Windsor the funeral of the recently deceased King George III. Harrison was confident that the remaining soldiers could be dealt with in the same way the cabinet would be-with a few well placed hand grenades and a barrel full of luck.