Good evening,
Lanyards always cause a little debate over who wore them, many see them and say "ARTILLERY". Not true, many regt's wore them. In fact, every soldier was issued with one but not all wore themon show.
There were however different styles, the one in your photo is the basic utility version. It is about 30 in long and is a large loop, a single length and a small loop.
Worn as shown it will most likely have a clasp knife attached to the small loop and placed in the pocket. It could also be a whistle for an officer.
The artillery version was about 6 ft long and was for firing the gun. It would be woven into a decorative item for wearing on the uniform.
John915