yep I think it is an Euphorbia that has the common name caper spurge. seeds prolifically all around. If you do decide to remove it be aware that the milky sap is a real skin irritant made worse be exposure to sun light.

Not euphoria if a child touches it. Wait for the flower to see which one it is. I think it might be the yellow flowers one.

Hi, yes it looks like caper spurge to me, Euphorbia lathyris, as Bramhallbill says, the one with the yellow flowers, only they're not actually flowers, they're cyathia, cupped by involucres of bright green bracts, followedby caper like fruits, Derek.

big thanks to you all i would never have known !