Hampton Court astronomical clock

The clock is 15 feet (4.6 m) in diameter with three separate copper dials revolving at different speeds and displays the following information: The latter information was of great importance to those visiting this Thames-side palace from London, as the preferred method of transport at the time was by barge.

Two consequences flowed: journey time, which departing around high water would speed instead of hinder; and all but the most skilled or reckless watermen above the bridge would avoid nearing London Bridge at times of great surface-water ebb under the (then famously built-up, barrage-like) bridge to avoid being swept into the starlings (cutwaters) or arches above.

In 1831 the mechanism was replaced with that of a 1799 clock from St James's Palace.

In 1879 the astronomical dials were rediscovered and replaced, and Gillett & Bland manufactured a new clock movement.

[5][6] The clock features both on the cover and in the plot of Robert Galbraith’s Troubled Blood.