A Traitor at Tower Bridge

In an effort not to bog the story down with too many facts and figures, a lot of the research for A Traitor At Tower Bridge never actually made it into the book. Most of it was fascinating, if ultimately irrelevant to the tale I had to tell.For example: the two halves of Tower Bridge that open, which really are called bascules, only open wide (and high) enough to accommodate whichever ship is passing through. They are only raised to their highest, an angle of 86 degrees, when the monarch is on board the vessel.