There are numerous qualifications that apply to Members of Parliament. One must be aged at least 18 (the minimum age was 21 until s.17 of the Electoral Administration Act 2006 came into force), and must be a citizen of the United Kingdom, of a British overseas territory, of the Republic of Ireland, or of a member state of the Commonwealth of Nations. These restrictions were introduced by the British Nationality Act 1981, but were previously far more stringent: under the Act of Settlement 1701, only natural-born subjects were qualified. Members of the House of Lords may not serve in the House of Commons, or even vote in parliamentary elections (just as the Queen does not vote); however, they are permitted to sit in the chamber during debates (unlike the Queen, who cannot enter the chamber).