Bang to rights
This expression is not heard or used very much these days but it means fair and square as in being caught or being beaten bang to rights and dates from the late 19th century. Eric Partridge, however, has it as underworld slang from the 1930s, but bang has been an intensifier signifying quantity or completeness from the early 19th century as in the whole bang shoot etc, while to rights. meaning rightfully, dates from the 1400s. The American version of this expression is dead to rights, which dates from the mid-19th century, a little earlier than the advent of bang to rights. See also Dead centre/certain/straight etc.