ID for this tall ?weed please

thanks, I've just looked through google images at the wild spurges, can't see it.
The detail of the leaf pair and the stem growing through the centre is a feature I've not often noticed, must be a botanical name for that type of leaf attachment. It is about as tall as a great willow herb, not seen any flowers on this mystery plant yet.

 

thanks, soapwort looks a close match with the stem growing through the center of a leaf pair, although the soapwort leaves don't look as big and wide, may have to get a better photo, or wait to see if it flowers

 

My initial thoughts were Himalayan Balsam, but that was before I looked at the 2nd image showing the junction of stem and leaves, then stumped.

Any flowers, seed capsules on it?

 

Only stem and leaves at the moment, about 4 feet tall now, been growing for a maybe a few months