Hogweed, not Giant Hogweed, and I thought it was only the Giant Hogweed that was dangerously poisonous but with a little research it seems that both varieties are poisonous with the roots being the most dangerous part of the plant.
The poison is commonly known as Hemlock and the Ancient Greeks were great users of the brew when they passed a sentence of death on someone, they provided the brew and you drank it. Saves money on an executioner I suppose and the cocktail finished that old trouble maker Socrates off too.
I stood watching the flies and bees supping the nectar on this Hogweed flower so the nectar can't be that strong or potent because they all flew off without even a wobble.
I'd better not tell the boss where this plant is, I think I'll just keep quiet about it.