The humble jack knife was issued to nearly all soldiers and sailors in the second world war. It was a useful tool that many of them kept after their return to civilian life.

There are several variations on the jack knife depending on period, service and manufacturer, including examples with spikes for opening out ropes.

The lanyard was passed around the waist, through the belt loops, and the knife dropped through the loop at the end, allowing it to be stored in the trouser pocket with no danger of it getting lost. 

This particular naval version is all steel, with a steel shackle dating it to late/post war.

good opening action, and in fair condition with some pitting to the steel.