This is the male of the sub species of Northern Wheatear known as 'Greenland' Wheatear. It is a passage migrant to the UK and only stops off here to refuel before making the most amazing of bird migrations from sub-Saharan Africa to Greenland and even the eastern seaboard of Canada, frankly astonishing! Additionally more recent discoveries from miniature tracking devices have also shown that it migrates across all of Eurasia to Alaska. One of the longest migratory flights known - 30,000km (18,640 miles). Alaskan birds must travel almost 15,000km (9,000 miles) each way - crossing Siberia and the Arabian Desert, and travelling, on average, 290km per day.
Superficially similar to the UK nominate race , but when compared side by side to the distinctly smaller local birds at this site leucorhoa is noticeably larger and brighter.
I think this individual is the of the Icelandic morph, although admittedly I am less certain of that.