A little bit of a debate has sprung up on BirdForum about this white-winged gull in the scarce birds gallery (you may have to scroll down some way):
Birdforum debate: http://www.birdforum.net/showthread.php?p=2006654
For what it's worth, I think DaveM has a fair point. To me, this big, bulky bird looks like a Glaucous Gull (more specifically, a 2nd-winter with an unusually dark eye), although that has been quashed on BF despite a pic showing it clearly dwarfing a Lesser Black-backed Gull behind.
What is interesting is the bird's similarity to this bird seen earlier in the winter in Oxfordshire:
This bird, a 2nd-winter with an unusually-dark eye, has also been seen recently at Throckmorton in Worcestershire (per Steve Whitehouse), which isn't too far from Stubber's Green (at least not in terms of gull movements).
To conclude, I think there is a very good chance one bird is involved with all sightings here - I know there has been a 2nd/3rd-winter Iceland at Stubber's this winter already, but surely this is not it. The bird Hughie King has photographed and put on surfbirds (granted the pictures aren't great - no offence Hughie) does not look like an Iceland Gull to my eyes, and in fact bears more than a passing resemblance to the Oxfordshire (and Worcestershire) Glaucous Gull, both plumage and structure-wise. Given that it is comparitively rare to find white-winged gulls retaining dark irises at an age of c.18 months, then this presumably strengthens the case. Surely the Stubber's Green bird is a Glaucous Gull.