An MP, or Member of Parliament, is an individual elected to serve in the House of Commons, the lower house of the Parliament of the United Kingdom). MPs are elected by all those who live in a particular area (constituency) to represent them in the House of Commons. They are responsible for acting in the national interest, as well as in the interests of their constituents, where this does not override their primary responsibility. If they belong to a political party, they may also act in the interests of that party, subordinate to the other two responsibilities). Some MPs from the governing party (or parties) become government ministers with specific responsibilities in certain areas, such as Health or Defence. To become an MP, a person must be at least 18 years old and be a citizen of the UK, a Commonwealth nation, or Ireland. A person is not required to be registered to vote, nor are there any restrictions regarding where a candidate is a resident).