Off-year European Parliament elections
From Infogalactic: the planetary knowledge core
Elections to the European Parliament are held every five years in all member states. Elections are held off-year in a country that has acceded to the European Union and must now send delegates.
Also, during the period when the United Kingdom used single-member, first-past-the-post constituencies to elect Members of the European Parliament from 1979 to 1999, they were required to have by-elections when a member resigned, died in office or was disqualified.
The following is a list of every off-year European Parliamentary election: