Caper Spurge

A few months ago, these plants started to grow in my garden. Weeds, I thought. (I was right, by the way.) But then I saw a question sent to the gardening section of a Sunday newspaper from someone who had exactly the same thing growing; the answer was just to leave it, as it's fairly attractive when it matures. Well, I'm not sure it's that attractive; it's now in full bloom but as the flowers are green, you wouldn't know it. But actually, they are quite nice in a wild flower sort of way. Apparently, it's a biennial, so I need to cut it down before the seeds spread or I'll have a bigger patch of them in two years time. A job for the weekend, I think.