Plant ID please
 

Just dug up a clump of something and divided it into three. Pale green leaves which are fairly tightly packed together. This one's in a pot 4 inches across the top. Don't think it's a poppy as the leaves are not that soft. Would love to know what it is. Don't remember planting it and it was in between some stepping stones and I would not have put it there. Can't see a similar plant nearby.