This is Convolvolus sepium commonly known as the dreaded bindweed. Convolvulus sepium are herbaceous perennials with spirally arranged heart shaped leaves and trumpet-shape white flowers. They are beautiful but troublesome as the vines twine around other plants, in a counter-clockwise direction, smothering other plants.

They are impossible to get rid of because of the creeping roots, that when cut into and left in the soil can grow into a whole new plant!
Taken by myself.