Hi there and thank you for replying. It was definitely not a wagtail, I am very familiar with them and most of the common birds in Cambridgeshire. It's back and head were predominantly white, that was what was so remarkable about it. It was flying away from me when I first saw it and it's back and wings looked almost entirely white. I only saw its grey belly when it was on the ground for a few seconds. I thought I would try picking the brains of the forum because it is something I have not found in any pictures anywhere and am stumped!
