As it turns out, it was on our Jack the Ripper tour, which we took (Dickie is a real Beefeater but moonlights as a Ripper tour guide). [EDIT: Here's a link to Ripping Yarns, the company for which he gives tours]
Just so y'know.
Here's the clip from our video.
Dickie was an awesome guide, which is why we decided to take HIS Ripper tour instead of any other. If you ever get a chance to go, be sure to do both his tours.