Representatives are elected in multi-member constituencies (usually between 3 and 7 representative members per constituency).
Instead of a single ‘X’ the voter ranks candidates in order of preference – a ‘1’ against their first choice, ‘2’ against their second; and so on. They do not have to rank all the candidates - just those they have an opinion on.
Candidates are elected if they achieve a sufficient share , or ‘quota’ of the votes. If a candidate has more votes than needed for election, surplus votes are transferred to the voters’ next preference. When a candidate with insufficient votes is excluded, their votes are passed on to the voters’ next preference. These transfers mean that votes are not wasted. People are empowered to vote according to their real preferences.
STV is used for Scottish local government; and optionally for Welsh local government (from 2027). It is used for all elections in Northern Ireland except UK General Elections and has been in use in Ireland since the country’s independence in 1921. It is the system preferred by the Liberal Democrats and the Scottish National Party.. Within political parties, STV is used for elections to the Labour Party National Executive Committee, for all internal Liberal Democrat Party elections, and for countless associations, institutes and unions across the UK. Even the Conservative Party uses a modified version (preferential voting in stages) to elect its leaders!