(known as special elections in the United States, and bypolls in India) are used to fill elected offices that have become vacant between general elections.
In most cases these elections occur after the incumbent dies or resigns, but they also occur when the incumbent becomes ineligible to continue in office (because of a recall, ennoblement, criminal conviction, or failure to maintain a minimum attendance). Less commonly, these elections have been called when a constituency election is invalidated by voting irregularities.
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Vincent Hanna: Good evening and welcome to the Dunny-on-the-Wold by-election. The first thing I must tell you is that the turnout has been very good. As a matter of fact, the voter turned out before breakfast. And I can bring you the result of our exclusive exit poll, which produced a 100-percent result for "Mind-Your-Own-Business-You-Nosy-Bastard."