hello,
Peaks this is true BTW. My mate (Veteran) former Royal Navy, Royal Marine Combat Engineers, & Royal Engineers (Suez, Aden, Radfan, Cyprus) he confirmed this as I was showing he my two Jack Knives (old & new) he also stated he made a lanyard for such as part of his training, & utilised such as a Sapper. He still has the lanyard at home.
Regards
David