Phylum: Basidiomycota Family: Strophariaceae
Stropharia pseudocyanea (Desm.) Morgan
Peppery Roundhead
A striking roundhead, turning blue with age starting with the stipe then the cap. A grassland species, not uncommon
References:
Noordeloos (2011) Fungi Europaei, 13: Strophariaceae
Hedger & George (2018) Lundy Fungi: a Photographic Guide