I glimpsed this 1st winter gull swimming at the back of the main group of loafing gulls and thought it was another Caspian. It then came closer and the more i looked at it the more i doubted it. Sometimes it looked perfect for a Casp' yet at other times it just didn't feel right, especially as the perfect colour ringed 2CY was nearby for comparison. The bill structure and head shape ruled out a michahellis and i also convinced myself (i think)that it couldn't just be a pale Herring Gull. It also lacked a good primary projection on the water (compare green 55PO) and this was also evident in flight. Maybe i had spent too long watching it or maybe i was just being a twat and it was clearly a ??. What i do know is that it well and truly mind f----d me and i was glad when it got dark.