Phylum: Rhodophyta   Family: Kallymeniaceae

Callophyllis laciniata  (Hudson) Kützing, 1843

Beautiful Fan Weed

Grows on rocks and as an epiphyte on kelp. Common around the British coastline and often found in winter in drift and on the strandline

References: 
Irvine (1983) - Seaweeds of the British Isles, Volume 1 Rhodophyta, Part 2A Cryptonemiales (sensu stricto), Palmariales, Rhodymeniales;
Bunker, Brodie, Maggs & Bunker (2017) - Seaweeds of Britain and Ireland