I think this is the widest band of blue I have ever seen around a Robin's breast.
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...can be indicative of a continental Robin, which has migrated here for the winter. However, proving this would not be possible, as some local birds can show this colour, too, on occasion.
My Flickr photos...
Lat/Lng: 52.246189700093, -1.775289773941
OS grid ref: SP154609
The location is close to overgrown paddocks previously grazed by horses