On Thursday, the Brits held what they call a "by-election." That means a special election in a parliamentary district to fill a vacancy that has occurred between general elections.
What makes this one memorable is that, for the first time ever, the United Kingdom Independence Party or UKIP won a seat in parliament. See a Reuters story for details.
UKIP is known for opposing UK membership in the European Union or EU. It also favors control of immigration, and to some degree occupies an analogous niche in UK politics to that occupied in French politics by the National Front. It is mostly thought to be a threat to the Conservatives.