1Debate on the Electoral Reform Referendum on how we elect our politicians to parliament, which is on Saturday September 19th. The vote will be to either, keep the First- Past-the-Post (FPP) system of to change to a Proportional Representation (PR) system, of which there are four types. The final and binding vote will take place at the 1993 election. Tonight's programme looks at the four PR types and how they perform throughout teh world.