Where can i get sannakji (live octopus) in london?

a friend told me about it so i looked it up on youtube and it looks amazing! i really wanna try new foods regardless of ethics so don't morally lecture me on it. is it legal in the uk? i know its a korean delicacy so are there any good authentic korean restaurants in or around central london (at least within like zone 4) where i could try it? cheers!