The Conservative and Unionist Party, commonly the Conservative Party and colloquially known as the Tories, is one of the two main political parties in the United Kingdom, along with the Labour Party. It is the current governing party, having won the 2019 general election, and has been the primary governing party in the United Kingdom since 2010. The party sits on the right-wing to centre-right of the political spectrum. It encompasses various ideological factions including one-nation conservatives, Thatcherites, and traditionalist conservatives. The party holds the annual Conservative Party Conference, at which senior Conservative figures promote party policy.

A two-party system is a political party system in which two major political parties consistently dominate the political landscape. At any point in time, one of the two parties typically holds a majority in the legislature and is usually referred to as the majority or governing party while the other is the minority or opposition party. Around the world, the term has different meanings. For example, in the United States, the Bahamas, Jamaica, and Zimbabwe, the sense of two-party system describes an arrangement in which all or nearly all elected officials belong to either of the two major parties, and third parties rarely win any seats in the legislature. In such arrangements, two-party systems are thought to result from several factors, like "winner takes all" or "first past the post" election systems. The electoral competition is mostly limited to the two major parties.