By elections to the House of Lords

Following the passing of the House of Lords Act 1999, the number of hereditary peers entitled to sit in the House of Lords was reduced to ninety-two. Ninety of the first ninety-two were elected by all the hereditary peers before the passing of the reform. Since November 2002, by-elections have been held to fill vacancies left by deaths of those peers. Since the passing of the House of Lords Reform Act 2014, by-elections have also been held to fill vacancies left by the resignation of those peers.

Before the passing of the 1999 Act, the Lords approved a Standing Order stating that the remaining hereditary peers shall consist of:

Elections must be held within three months of a vacancy occurring and take place under the Alternative Vote system. All those on the Register of Hereditary Peers are eligible to stand, but only sitting (the "excepted") hereditary peers may vote (which can result in very small electorates, such as three voters in the 2003 election of Lord Grantchester).

As of January 2017^[update], the current party affiliation of the hereditary peers is:

After the death of the Viscount of Oxfuird:

After the death of Lord Milner of Leeds:

After the death of Lord Vivian:

After the death of the Earl Russell:

After the death of Lord Burnham:

After the death of Lord Aberdare:

After the death of Baroness Strange:

After the death of Lord Mowbray and Stourton:

...
Wikipedia