Electoral systems vary from one Member State to another. Whereas some have a first-past-the-post voting system, others vote according to proportional representation or to a voting system which is a combination of the two. Some countries, such as Luxembourg, allow electors to vote for more than one party, others set up national or regional constituencies. There is no set pattern, and the differences affect both the election results and the composition of the European Parliament.
The representativity of Members of the European Parliament also differs depending on the country. Although the allocation of seats between Member States tries to reflect the size of their respective populations, the allocation is still not strictly proportional. The small countries, such as Luxembourg, which has one MEP per 60 000 inhabitants, are comparatively over-represented while larger countries, such as the Federal Republic of Germany, which has one MEP per 765 000 inhabitants, are significantly under-represented.
Nor are the national provisions of the Member States with regard to dual mandates entirely the same. Only the United Kingdom, the Netherlands and Ireland grant voting rights to nationals from other Member States of the European Community residing on their territory.
Voting day, which also affects the final outcome of the ballot, likewise varies from country to country in accordance with national policy traditions. Whereas voting is held on a Sunday in most EC countries, it is held on a weekday in Great Britain and in the Netherlands. Only in Belgium and Luxembourg is voting mandatory.