When I was clearing out my father’s business premises I came across a trench saw from World War I.
It was made by Francis Wood and Sons, Sheffield and was for cutting down trees and making props for the sides of dugouts, etc. Constructed like a bicycle chain it could be stored in the leather pouch that has loops so it could be worn on a belt.
The helmet is a bit of a mystery. It may be from the First World War, but it could be from a more recent time such as the Second World War.