I think this is Red-necked Phalarope and probably a molting juvenile. Or could it be a Red Phalarope? I think the red Phalarope has a shorter bill and the neck is much more reddish. Is there any other way to confirm this.
I work on these birds when they are on migration and in their winter, Basic plumage. This is indeed a Red-necked Phalarope. As mentioned the bill on this bird is relatively long and thin, whereas the Red Phalarope (Grey Phalarope in Europe) has a shorter, thicker bill. This bird also has a fairly dark, scaly back; the Red/Grey Phalarope would show a much plainer marked, lighter grey back. I agree this is probably a juvenile bird- adults are lighter on the back than this.