[Bidimus1]

I guess they have been reading Black Book 1 & 2 by US Army
or just history books about some of the weapons UK was putting into service in 1940

http://en.wikipedia.org/wiki/British_anti-invasion_preparations_of_the_Second_World_War

[Bidimus1]

more..

http://militaryhistorynow.com/2014/03/31/dads-armaments-six-impromptu-weapons-of-the-british-home-guard/

http://en.wikipedia.org/wiki/Smith_Gun