Within the last few months, the Gardeners' World TV show had a chap on who collected/grew tall, green possibly African shrubs.
I think I have one on my garden. It has four stems, symetrically all the way up the main stem. It has little pumpkin like seed pods which are green. Long thin leaves all over. Bees love it. It's about 4 ft high now. I thought it was a weed. Never seen one before having this garden. In Worcestershire.
The sap, on snapping a stem, splittered all over me and now I have itchy, red rashes where it touched my skin. Including my face. Very painful.
What is the plant? I have photos!.