Reeves's Pheasant Syrmaticus reevesii
This species is not on the main British list as the feral population is so small it is not yet recognised as being self-sustaining. Nevertheless they seem to be becoming increasingly easy to find in the Norfolk Brecks where they almost certainly outnumber Golden Pheasants now. This population seems to contain a disproportionately high number of males, the reason for which is so far unclear. There are apparently a number of other locations around the country where this species seems to be gaining a foothold, so perhaps it won't be long before they are recognised as British bird.
Hybrids between this species and Common Pheasant are also appearing - photos here.
The following individuals presumably did not originate from this population, as they were some distance away.
The first was extremely tame and was presumably an escape from captivity:
female Reeves's Pheasant, Bircham Newton (Norfolk, UK), 7th April 2005
Two males of unknown origin, probably escaped but perhaps feral, appeared near Buckenham recently:
male Reeves's Pheasant, Buckenham (Norfolk, UK), 20th April 2007