There are a lot of these around at the moment. It's quite a challenge to identify wildflowers using the web. If you already know the name, there are plenty of sites that can then show photos and other details. But how to find the name? A fairly generic google image search of "purple wildflower uk summer" didn't turn up much: a couple of similar plants and someone who was also trying to find the name. One solution is to use Google's Advanced Image Search: www.google.com/advanced_image_search I left everything blank or at its default except "Site or domain" where I put wildflowerfinder.org.uk This resulted in a long long page of images just from the above website and after some scrolling, a positive id on the flower. It's a Rosebay Willowherb.