And in that respect all I'm saying is it seems odd to that in wartime during a known shortage that BSA could propose building a decent SMG at £5/unit and the procurement agencies not replying back "Fantastic! Where do we back up the trucks?"
Because BSA didn't have factories sitting ideal with men twiddling their thumbs, they were the primary private producer of No.4's, were making .303 Brownings for the RAF, Oerlikon cannons for the RN, Boys Anti-tank rifles and plenty of other stuff so the Ministry of Supply probably decided that adding bringing a new weapon system into production order would cause disruption to more important contracts. It would be the same logic that they applied to the switch over from 2-pounder production to 6-pounder. They also probably felt that they didn't want to be producing a two SMG's at the same time so it was an either/or situation and the Sten got the nod.