White flowered clematis
Introduction
The photograph on this page of White flowered clematis by Jonathan Billinger as part of the Geograph project.
The Geograph project started in 2005 with the aim of publishing, organising and preserving representative images for every square kilometre of Great Britain, Ireland and the Isle of Man.
There are currently over 7.5m images from over 14,400 individuals and you can help contribute to the project by visiting https://www.geograph.org.uk
Image: © Jonathan Billinger Taken: 12 May 2017
I think the variety may be 'Avalanche'.