What is the symbol for British standards?

Excuse me, could you kindly clarify something for me? In relation to quality assurance and regulatory frameworks, I've often encountered references to various standards bodies and their respective symbols. Now, I'm particularly interested in the symbol that represents British standards. Could you please elaborate on what that symbol is? It's quite important for me to be able to identify it accurately in order to ensure compliance with relevant regulations in my field of work. Thank you for your assistance in this matter.