how long can a uk government remain in office before they have to hold a general election
Elections in the United Kingdom A general election must take place before each parliamentary term begins. Since the maximum term of a parliament is five years, the interval between successive general elections can exceed that period by no more than the combined length of the election campaign and the time for the new parliament to assemble (a total of typically around four weeks). The five years runs from the first meeting of Parliament following the election.
Age of candidacy In the UK (other than in Scotland) a person must be aged 18 or over (16 in Scotland) to stand in elections to all parliaments, assemblies, and councils at the European, UK, devolved, or local level. This age requirement also applies in elections to any individual elective public office; the main example is that of an elected mayor, whether of London or a local authority. There are no higher age requirements for particular positions in public office. Candidates are required to be aged 18 on both the day of nomination and the day of the poll. This was reduced from 21 by the Electoral Administration Act 2006.