According to the book Vimy Ridge by Pierre Berton the Canadians were taught from the start of their training (in Canada), by Currie, not to take prisoners unles

According to the book Vimy Ridge by Pierre Berton the Canadians were taught from the start of their training (in Canada), by Currie, not to take prisoners unless specifically instructed to do so, say to obtain information under interrogation later. It was official policy not an emotional reaction. Currie was very self-made as a military man and may have come up with that policy on his own. Or not.