London – Kensington and Chelsea (Borough of) – National Army Museum (Ration Biscuit)
I’ve seen ration biscuits that have been sent home in many museums, they weren’t particularly popular with troops and they did make for useful souvenirs. Bread couldn’t be distributed because it went mouldy, so members of the armed forces received these dried things usually made from flour, water and salt, which then had to be mixed with a liquid to become vaguely edible.
The National Army Museum has this item on display, sent back home by Trumpeter S Foster from the 12th (Prince of Wales’s Royal) Lancers. It can’t be seen from how the museum has presented it, but on the rear is the receiver’s address and two postage stamps, so it really did go through the postal system. I imagine that amused the postal authorities and it is remarkably undamaged given its journey from South Africa.