There has always been a need to send valuable items by mail hence the introduction of the registration system.  One very overlooked part of this service, due almost totally to the essential need for secrecy, is the transport of banknotes for the Banks by Royal Mail. In a "cash" society there was a need to transfer new banknotes and despatch used notes for checking and/or destruction; also a need to repatriate banknotes to their regional banks.  This service was provided by Royal Mail from the early1930s. These "mailbags" were heavy and this required very high postal rates thus creating a rare source of commercially used high value stamps on the mailbag tags often in very colourful combinations.  The Great Train Robbery of 8th August 1963 was directed at the HVP carriage containing the banknotes.  We have been fortunate to acquire almost all of the known used examples of the surviving mailbag tags.

Please remember that these bags would have been handled by railway staff and not stamp collectors so one should expect some creasing to the tags!