Hi Maeve!
I can see what you mean, and this plant isn't native to England. But actually the one specimen I had in my last garden didn't produce any babies, (I was quite sad!) But if it's becoming invasive, it could indeed harm children, walkers etc. I know that for example Japanese knotweed is the most terrible problem now that it's arrived here. Areas have been sectioned off as 'biological hazards', it takes industrial strength stuff to eradicate it. I only meant to say that I personally quite liked the thing. I wouldn't naturally want a child to be burned. Euphorbias and even the herb rue have the same properties, their juice causes sunlight burns. I had this happen from my rue bush last year. The brown marks are still on my arms!