It's Caper Spurge, Euphorbia lathyrus. It does have flowers, but you might not recognise them as such. You can see the green seed pods forming now. It's often sold as a mole-deterring plant. I would regard it as a weed in my garden.

It's already flowered - those bobbly bits are seed pods - for goodness sake don't wait for them to ripen and explode. It's a biennial (ie dies after the second year) so it is relatively easy to control as long as you don't let the seeds escape.
It's toxic and the sap is irritant - wear gloves when you remove it don't let the sap anywhere near your eyes (wash your hands thoroughly after handling, even if you have been wearing gloves)

Ok Thankyou for your replys I think I might get rid of it.