Trench or police whistle?

[funkeegirl81]

My father has a whistle with regp bukta B2 stamped on the barrel at the top of the whistle has patent 5727-08 attached is a leather wrist strap. I’m trying to research it but just coming to a dead end. I’m thinking it a police whistle but not seen any with these markings on. Any ideas?

On another note i have one with C.W.S stamped on it any ideas what that stands for?

Thanks 😊