Under the Scots law, a person may be guilty if he/she aids in or contributes to the commission of a crime committed by another, although he/she does not actually execute the crime. Such person may become guilty by:
1. advising or counseling another person to commit the crime;
2. assisting another to commit the crime; and
3. participating in the crime.
Scots law never distinguished between degrees of participation in a crime. In treason all participants in a crime were considered as principal offenders and indictments in other cases charged the accused as “actor or art and part.”