Simon Alexander Neil is a Scottish singer, guitarist and songwriter. He is known for his work in the bands Biffy Clyro, Marmaduke Duke, and also Empire State Bastard, with Mike Vennart.

James Robert Johnston is a Scottish bassist, vocalist, and songwriter, best known for his work with Scottish group Biffy Clyro. He is also known as Jim or Jimbo and sometimes signs his name as such.