One of the common thong like seaweeds found around our shores and can be easily confused with other strap or lace like seaweeds.
Normally found in the low to middle intertidal zone it's quite easy to see around the northern European coastlines. It's also called whip weed, mermaids tresses and boot lace weed. It is edible and high in antioxidants but not often consumed by people, it's ok and worth a try if you're feeling peckish. It can be dried and then broken up and added to stews and soups to provide a deeper saltier flavour.