Confidence: It's likely to be this, but I can't be certain.
Notes: Disregarding, for the moment, the fact that very few Russula species can be named from a photograph, this could be R. nitida. True R. sphagnicola is a synonym, according to Kibby's new Russula account, but the name sphagnicola (e.g. in Courtecusisse & Duhem) has been misapplied to what we should, apparently, be calling R. robertii. In view of the rich cap colour and rather strongly ochre gills, this is not R. robertii. I am not, however, convinced that it is this complex of species at all. It looks very robust, and the habitat as far as can be judged from the photographs may not be correct.