The Parliament is directly elected by the people of Europe once every five years.  This gives the 751 MEPs a unique and powerful voice. 

The Parliament legislates (alongside the Council), provides oversight of the Commission and, perhaps most significantly, the entire EU budget must be approved by the Parliament.  The Parliament also reserves the right to veto trade deals, as occurred in the case of Anti-Counterfeiting Trade Agreement (ACTA).  This gives MEPs a significant influence over the development of EU policy.  Scotland has 6 MEPs.