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 peers 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. Hereditary peers wishing to stand in a by-election are listed in a register of hereditary peers, maintained and published by the Clerk of the Parliaments.
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. These peers are voted for by the whole House.
Replacements for vacancies among the remaining 75 peers 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.
