Going through some old photos I came across this which I had identified as a juvenile Common Redstart, based on the red tail. However apart from the reddish looking tail, it does look rather like a juvenile European Robin in shape and stance as well as plumage, plus it was in the middle of the lawn, which seems a bit atypical for Common Redstart. So I began to wonder whether it could in fact be a European Robin with an unusually rufous-looking tail?
Common Redstarts do not nest locally, but I believe juveniles can move quite a distance from where they were raised, once fledged.