Dark duck with grey flanks. Blue bill with black tip. Yellow eye. Amongst mallards but possibly female tufted duck.
No interactions present.
This is a drake that has moulted into eclipse plumage indicated by the paler grey/brown patches on its sides.
It will moult its body feathers again later in the year back to its black body with white sides breeding plumage
Many thanks for helping with identification and for moulting information.
Lat/Lng: 52.3189, -0.1757
OS grid ref: TL244705