The ceremony of the Constable's Dues takes place at the Tower of London today: expect pomp and ceremony in abundance.
The historic ceremony originated in the 14th century, when naval vessels sailing down the Thames were forced to pay a toll to the constable of the Tower of London. In the past, dues have included barrels of rum and even shellfish.
Today from 12.20pm, officers from the HMS Richmond will present the Lieutenant of the Tower with a barrel of wine as a symbol for passing up the river.
The ceremony will be officiated by Debra Whittingham, the Tower's duty governor.
You'll be able to watch it on the Tower's Facebook page - and here - from 12.20pm.