The constitutional theory

In Fiji, the Leader of the Opposition is a senior politician who commands the support of the Official Opposition.
The Leader of the Opposition is, by convention, the leader of the largest political party in the Parliament of Fiji that is not in government.
This is usually this is the parliamentary leader of the second-largest caucus in Parliament.
It did not originate in Fiji but has a long tradition; in British constitutional theory, the Leader of the Opposition must pose a formal alternative to the government, ready to form a government himself should the Prime Minister lose the confidence of the parliament.