Tankie is right again about the old No4 rifle slings. They were truly versatile bit of kit. They would support tremendous loads and most people, including me kept one in their kit, usually rolled up in the poncho roll or tucked out of the way. The later nylon ones were strong enough but would slip through the buckles when they got wet. The training wing here have a big bucket of them for use in the FIBUA village where they're used during the street fighting and house clearing as generally useful bits of kit. The little Sterling sling was useful too and for many years I used to use one on an SA80 until 'advised' by those that matter that it set the wrong tone.

I don't know what this has got to do with Brens but there you go............