The House of Lords Act 1999 disqualified all hereditary peers for membership of the House, but excepted from this general exclusion 90 hereditary peers and the holders of the offices of Earl Marshal and Lord Great Chamberlain. From the end of the 2001-02 parliamentary session, section 2(4) of the 1999 Act and Standing Order 10 provide for a vacancy among any of the 90 excepted hereditary peers to be filled by means of a by-election. Paragraph (5) of Standing Order 10 requires the Clerk of the Parliaments to maintain and publish annually a register of hereditary peers (other than peers of Ireland) who wish to stand in any such by-election.

The following hereditary peers have indicated their wish to stand in any by-election under Standing Order 10. This list includes both hereditary peers who were members of the House before the enactment of the 1999 Act, and hereditary peers who have succeeded to their peerages since the 1999 Act or were not previously in receipt of a writ of summons and have been added to the register under Standing Order 11 in the case of those added since 23 January 2001, or who satisfied the Crown Office of their succession before that date.

Lords may join or leave the register at any point. Up-to-date information may be obtained from the Clerk of the Journals, House of Lords, London SW1A 0PW.

Aberdare, L.

Abergavenny, M.

Abinger, L.

Addison, V.

Aldenham, L.

Aldington, L.

Alexander of Tunis, E.

Amherst of Hackney, L.

Annaly, L.

Ashbourne, L.

Balfour, E.

Bedford, D.

Belper, L.

Biddulph, L.

Birdwood, L.

Birkett, L.

Bolton, L.

Boston, L.

Brentford, V.

Bristol, M.

Burnham, L.

Cadman, L.

Cairns, E.

Calverley, L.

Camoys, L.

Carew, L.

Carlisle, E.

Cawley, L.

Chesham, L.

Clancarty, E. (V. Clancarty)

Clanwilliam, E. (L. Clanwilliam)

Clifford of Chudleigh, L.

Clydesmuir, L.

Cobham, V.

Combermere, V.

Cork and Orrery, E. (L. Boyle)

Cowley, E.

Cranbrook, E.

Cromer, E.

Cromwell, L.

Daresbury, L.

Darling, L.

Daventry, V.

Davies, L.

De La Warr, E.

De L'Isle, V.

De Ramsey, L.

Devonport, V.

Drogheda, E. (L. Moore)

Dudley, L.

Dundonald, E.

Effingham, E.

Enniskillen, E. (L. Grinstead)

Fortescue, E.

Gage, V. (L. Gage)

Gainford, L.

Gladwyn, L.

Glanusk, L.

Gormanston, V. (L. Gormanston)

Grantley, L.

Gray, L.

Grimthorpe, L.

Hacking, L.

Halifax, E.

Hanworth, V.

Hardinge, V.

Harlech, L.

Head, V.

Herbert, L.

Hereford, V.

Hill, V.

Hindlip, L.

HolmPatrick, L.

Hood, V.

Iddesleigh, E.

Inchyra, L.

Ironside, L.

Iveagh, E.

Kenilworth, L.

Kennet, L.

Killearn, L.

Kimberley, E.

Kinnoull, E. (L. Hay)

Latymer, L.

Lawrence, L.

Layton, L.

Leathers, V.

Lichfield, E.

Limerick, E. (L. Foxford)

Mackintosh of Halifax, V.

McNair, L.

Macpherson of Drumochter, L.

Margadale, L.

Massereene and Ferrard, V. (L. Oriel)

Melville, V.

Meston, L.

Milford, L.

Milner of Leeds, L.

Milverton, L.

Minto, E.

Monckton of Brenchley, V.

Monk Bretton, L.

Monkswell, L.

Morris, L.

Morris of Kenwood, L.

Mountgarret, V. (L. Mountgarret)

Mowbray, Segrave and Stourton, L.

Napier and Ettrick, L.

Napier of Magdâla, L.

Nelson of Stafford, L.

Newall, L.

Norrie, L.

Nunburnholme, L.

Ogmore, L.

Oranmore and Browne, L. (L. Mereworth)

Oxfuird, V.

Pender, L.

Penrhyn, L.

Polwarth, L.

Poole, L.

Rathcavan, L.

Renwick, L.

Revelstoke, L.

Rowallan, L.

Runciman of Doxford, V.

Rutland, D.

St Davids, V.

Samuel, V.

Scarbrough, E.

Seaford, L.

Sempill, L.

Shaftesbury, E.

Shannon, E. (L. Carleton)

Somerset, D.

Spens, L.

Stair, E. (L. Oxenfoord)

Stockton, E.

Strange, L.

Strathcarron, L.

Strathmore and Kinghorne, E.

Sudeley, L.

Sutherland, D.

Swansea, L.

Swinton, E.

Terrington, L.

Teviot, L.

Teynham, L.

Tollemache, L.

Torrington, V.

Tryon, L.

Vaux of Harrowden, L.

Vernon, L.

Vivian, L.

Weir, V.

Wharton, L.

Wilton, E.

Woolton, E.

Yarborough, E.

Younger of Leckie, V.