Apparently in very poor condition, or moulting like there's no tomorrow.
No interactions present.
Though it seemed to be feeding ok, and it managed to fly, too. I don't think I've ever seen one looking quite this awful.
This, of course Si, is a recognised bird. 15 people think so - but then you haven't agreed!
Perhaps the title should be changed to Poor little Sod. Perhaps!
Title changed. I suspect you're going to be in touch again...
Lat/Lng: 52.2477, -0.24862
OS grid ref: TL196625