It began when the Lord Mayor of London branded oak carts, marked them valid to ply for trade of goods from the wharves of the Thames into the City of London; five shillings were paid to provide haulage.
Today it has become a ceremonial event - a variety of pre-1950 vehicles are chosen to carry the oak board representing those original oak carts; each oak board branded with a year letter.
The Express sector is too new for pre-1950 so finds itself absent from the July ceremony, but the board is displayed from previous Carmen events.