That right there is the work of someone who has spent time in the Western Frontier of Pakistan.
Don't bet on it. My guess is that submachinegun is purely the product of Canadian gun control laws.
The British Sten and the Russian PPSh were specifically designed to be built in local garages or metal working shops and the plans exist on the internet. You don't have to go 8000 miles to find people who can build weapons. Besides, the guys in Pakistan seem to only produce copies. The sub gun in the picture looks like a basic Sten design, with the charging handle on the left side, but the magazine has been relocated to the bottom giving the gun better balance during recoil and less tendency to string to the right. That's the kind of simple but original modification that a home gunsmith might make but the Pakistanis probably wouldn't.
I wonder where they got their barrel? Possibly an old UZI or other 9mm carbine.