The Pearly Kings and Queens ideal originates in 19th century amongst the Costermonger apple sellers, who wore clothes decorated with pearl buttons, and were famous their charitable spirit.
However, it wasn't formalised until 1875, when Henry Croft, an orphan street sweeper, decided to adopt the clothes of the Costermongers and collect money for his former orphanage. He was so successful that other organisations asked him to collect and the celebrated working class charitable idea properly emerged, and in 1911 an organised pearly society was formed.
Today, despite disagreements between the Original London Pearly Kings and Queens Association, the rival London Pearly Kings and Queens Society, and the Pearly Guild, the tradition is strong and this afternoon the former association will meet at St-Martin-in-the-Fields for their harvest festival, and to collect money for charity.
The day runs from noon at 4pm, with a formal church service beginning at 3pm, but the kings and queens will be out in force before. For more information, see http://www.thepearlies.com/