Phylum: Ochrophyta   Family: Fucaceae

Fucus spiralis Linnaeus, 1753

Spiralled Wrack

Growing on rocks in the upper intertidal zone. Superficially similar to other species, but easily identified. Very common all round the British coastline

References: 
Fish & Fish (2011) - A Student's Guide to the Seashore;
Bunker, et al - Seaweeds of Britain and Ireland