Second Great War

Back home after a few days away with work and we took an afternoon stroll around our home town. We stumbled across this memorial to the local men who fought and died during the Second World War. It's on Romney Road in Kendal and I've never noticed it before. What I found strange though is the title on the plaque, Second Great War. I've genuinely never heard it referred to in such a way. Is this an old phrase which has slipped from common usage? Or is it a mistake?