Help! Border Invader

Magic!
I have googled symphytum and you ar absolutely right, it is white comfrey.
Thank you all so much.
Now the only quandry left is what to do with it ..... I think I shall pot some up, keep it for making some of Stingo's 'smelly' liquid feed and bury the rest, apparently it is an excellent green manure.

 

Excellent Vistabile

I tear the leaves off and put them into a bucket, cover with water and then wait for it to infuse? is that a word? when it's gone dark and smelly! pour a bit into my watering can top up with water and spray over flowers; then the splodge that's left I add to the compost bin or just onto the border. I seem to be able to keep my bit under control by digging up what I don't need and then tearing off the leaves, putting into a bucket, adding water.......etc etc :D