Redpolls vary both in size and in shade of brown. The Icelandic variety is the palest and has whiter wing bars and less streaked underparts than others.
Today I saw two unusually white Redpolls which resemble the Arctic Redpoll a lot. They are probably just ordinary Redpolls but quite unlike the normal Icelandic Redpoll. This is one of the whiter ones
and this is the other one. Below is a normal Icelandic Redpoll.