Smarties are chocolate beans introduced by Rowntrees in 1937 plastic lids were used on the tube in the 1950s and in the 1960s letters and sometimes numbers were added to the underside of the lids as a useful teaching aid, making them highly collectible for children. The lids have undergone many changes over the years in the early 1990s Nestle bought out Rowntrees and the Rowntrees wording disappeared being replaced with 'Smarties'.
In February 2005 hexagonal tubes were designed with an integral hinged cardboard lid omitting the need for the plastic lid that was so much a part of childhood memories.
People are fascinated by the history, the length of time these lids have been floating around in the sea and how they get there in the first place. Whole alphabets are being collected and limited editions are sought after.
My collection of smartie lids has reached over 300, and I was gifted a very special imperial sized one dating from between 1960 and 1970.