The House of Lords Act 1999 removed most hereditary peers from the House of Lords. Under the Act, 90 hereditary peers retained their places, elected by their fellow party/group colleagues to remain as Members. Since the start of the 2002–03 session, when one of the 90 hereditary peers dies, retires or is excluded, a replacement is chosen in a by-election.
There are two different types of by-election. Of the 90 hereditary peers, 15 were elected to provide the House with Members able to act as Deputy Speakers and other office-holders. They are voted for by the whole House. Replacements for vacancies among the remaining 75 are voted for by the other hereditary peers in a particular party or by the Crossbench hereditary peers. In 1999, the 75 seats were allocated proportionally to reflect the affiliations of the hereditary peers who sat prior to the House of Lords Act. Consequently, for the purposes of by-elections, 42 are elected by Conservative hereditary peers; two are elected by Labour hereditary peers; three are elected by Liberal Democrat hereditary peers; and 28 are elected by Crossbench hereditary peers.
In addition to these 90 Members, two peers—the Earl Marshal and the Lord Great Chamberlain—remain Members of the Lords by virtue of the royal offices they hold. Some hereditary peers who were Members of the House prior to the 1999 Act were also given life peerages.
