During its history, the United Kingdom (and previously the Kingdom of England, Kingdom of Scotland and Kingdom of Ireland) has seen many families who have repeatedly produced notable politicians, and consequently such families have had a significant impact on the politics of the United Kingdom (and in some cases, the politics of the Republic of Ireland).

Certain families, such as the Cecils, owe their long-standing political influence to the composition and role of the House of Lords, which was still mainly composed of hereditary legislators until the passing of the House of Lords Act 1999. Other families, such as the Longs, have had a long tradition of standing for elected office, usually in the House of Commons. Many such families were part of the landed gentry, who often exerted political control in a certain locality over many generations.

(Dyke-)Aclands Sir Thomas Dyke Acland, 11th Baronet, MP 1837–86 Sir Thomas Dyke Acland, 12th Baronet, MP 1882–92. Elder Son of 11th baronet. Sir Arthur Dyke Acland, 13th Baronet, MP 1885–99. Younger Son of 11th baronet. Sir Francis Dyke Acland, 14th Baronet, MP 1906–39 Richard Acland, MP 1935–55.

Adamses Allen Adams MP Irene Adams MP and life peer. Spouse of the above.

Adamsons William Adamson, MP 1910–31 William Murdoch Adamson, MP 1922–45.

Aitkens William Maxwell Aitken (1879–1964), MP 1910–1916, later 1st Baron Beaverbrook Max Aitken, Conservative MP 1945–1950, later 2nd Baron Beaverbrook; son of Lord Beaverbrook William Traven Aitken (1903–1963), Conservative MP 1950–1963; nephew of Lord Beaverbrook Jonathan Aitken (born 1942), Conservative MP 1974–1997, Chief Secretary to the Treasury; son of William Traven Aitken

Alderdices John Alderdice, Baron Alderdice (born 1955), leader of the Alliance Party David Alderdice, Lord Mayor of Belfast. Brother of the above.

Alexanders Wendy Alexander (born 1963), MSP for Paisley North since 1999, Minister in the Scottish Executive 1999–2002, Shadow Finance Secretary 2007 Douglas Alexander (born 1967), Labour MP for Paisley and Renfrewshire South. Brother of the above.

Atkins Robert Atkins, Conservative MP 1979–1997 and MEP 1999–2014MPs related to other current or former Members in the 2017 Parliament, House of Commons Library, 26 September 2017. Victoria Atkins, Conservative MP 2015–. Daughter of Robert.

Attlees Clement Attlee, Labour Prime Minister John Attlee, 3rd Earl Attlee, accepted hereditary peer; grandson of Clement

Amerys Leo Amery (1873–1955), Conservative MP for Birmingham Sparkbrook 1911–1945, Secretary of State Julian Amery (1919–1996), Conservative MP for Preston North 1950–1966, Brighton Pavilion 1969–1992, Secretary of State for Air; son of Leo; also son-in-law of Harold Macmillan (see below)

Armstrongs Ernest Armstrong (1915–96) Labour politician Hilary Armstrong (born 1945) succeeded her father as MP for North West Durham in 1987, retaining the seat until 2010 when she retired.

Asghars

Mohammad (Oscar) Asghar (1945–2020), Conservative Member of the Senedd for South Wales East Natasha Asghar, Conservative Member of the Senedd for South Wales East; Mohammad's daughter

Astors Waldorf Astor (1879–1952), Conservative MP for Plymouth, Sutton 1910–1919, later 2nd Viscount Astor; husband of Nancy Astor, Viscountess Astor Nancy Astor (1879–1964), Conservative MP for Plymouth, Sutton 1919–1945, first female MP to take her seat; Waldorf's wife William Astor (1907–1966), Conservative MP for East Fulham 1935–1945, Wycombe 1951–1952; Waldorf and Nancy's son William Astor (born 1951), excepted hereditary peer; William's son David Cameron (born 1966), Conservative Prime Minister; stepson-in-law of William Waldorf Michael Astor (1916–1979), Conservative MP for Surrey East 1945–1951; Waldorf and Nancy's son Jakie Astor (1918–2000), Conservative MP for Plymouth Sutton 1951–1959; Waldorf and Nancy's son John Jacob Astor (1886–1971), Conservative MP for Dover 1922–1945, later 1st Baron Astor of Hever; Waldorf's brother Hon. John Astor (1923–1987), Conservative MP for Newbury 1964–1974; John Jacob's son John Jacob Astor (born 1946), excepted hereditary peer; John Jacob's grandson

Asquiths

H. H. Asquith (1852–1928), Liberal MP, Chancellor of the Exchequer 1905–1908, Prime Minister 1908–1916, later 1st Earl of Oxford and Asquith Raymond Asquith, 3rd Earl of Oxford and Asquith (born 1952), excepted hereditary peer; great-grandson of H. H. Asquith. Violet Bonham Carter (1887–1969), daughter of H. H. Asquith. (see Bonham Carters)

Bagshaws John Bagshaw, MP 1835–59 Robert John Bagshaw, MP 1857–59. Son of John.

Bakers Richard Baker MSP Claire Baker MSP. Spouse of Richard

Baldwins Alfred Baldwin (politician) (1841–1908), MP for Bewdley 1892–1908 (Conservative). Stanley Baldwin (1867–1947), MP for Bewdley 1908–1937 (Conservative), Prime Minister. Son of Alfred. Oliver Baldwin, 2nd Earl Baldwin of Bewdley, MP for Dudley 1929–1931, Paisley 1945–1947 (Labour). Son of Stanley.

Bankeses Henry Bankes, MP 1801–31 William John Bankes, MP 1810–34. Son of Henry. George Bankes, MP 1816–56. Son of Henry.

Barings Alexander Baring, 1st Baron Ashburton, MP 1806–35 and peer. Bingham Baring, 2nd Baron Ashburton, MP 1826–48 and peer. Francis Baring, 3rd Baron Ashburton, MP 1830–57 and peer.

Basses Michael Thomas Bass, MP 1848–83 Michael Bass, 1st Baron Burton, MP 1865–86. Son of Michael. Hamar Alfred Bass, MP 1878–98. Son of Michael.

Bathursts Seymour Bathurst, 7th Earl Bathurst, peer. Allen Bathurst, Lord Apsley MP Violet Bathurst MP. Spouse of Allen Henry Bathurst, 8th Earl Bathurst, peer. Son of Allen and Violet.

Beaumonts Colonel Thomas Richard Beaumont (1758–1829), soldier, Tory MP for Northumberland, 1795–1818 Thomas Wentworth Beaumont (1792–1848), soldier, son of Thomas Richard Beaumont, Tory MP for Northumberland 1816–1826, Whig MP for Stafford, 1826–1830, Liberal MP for Northumberland, 1830–1832, and for South Northumberland, 1832–1837 Wentworth Beaumont, 1st Baron Allendale (1829–1907), eldest son of Thomas Wentworth Beaumont, industrialist, Liberal MP for South Northumberland, 1852–1885, and for Tyneside, 1886–1892 Wentworth Beaumont, 1st Viscount Allendale (1860–1923), eldest son of Wentworth Beaumont (1st Baron Allendale), politician, Liberal MP for Hexham, 1895–1907 Ralph Beaumont (1901–1977) second son of Wentworth Beaumont (1st Viscount Beaumont), soldier, Conservative MP for Portsmouth Central, 1931–1945 Hubert Beaumont (1864–1922), third son of Wentworth Beaumont (1st Baron Allendale), Liberal MP for Eastbourne, 1906–1910 Michael Beaumont (1903–1958), soldier, son of Hubert Beaumont and son-in-law of Joseph Albert Pease (below), Conservative MP for Aylesbury, 1929–1938 Timothy Beaumont, Baron Beaumont of Whitley (1928–2008), clergyman, publisher and politician, son of Michael Beaumont and grandson of Joseph Albert Pease (below), Liberal, Liberal Democrat and from 1999 Green Party member of the House of Lords 1967–2008 Somerset Beaumont (1835–1921), third son of Thomas Wentworth Beaumont, banker, Liberal MP for Newcastle upon Tyne, 1860–1865, and for Wakefield, 1868–1874

Beckfords

Beckford family

Beggses Roy Beggs, former MP for East Antrim Roy Beggs Jnr., Member of the Legislative Assembly for East Antrim; his son

Beith Alan Beith, MP for Berwick-upon-Tweed 1973–2015 Diana Maddock, MP for Christchurch 1993–1997. Spouse of Alan.

Benns Sir John Benn, 1st Baronet (1850–1922), Liberal MP. Sir Ernest John Pickstone Benn, 2nd Baronet, first son of John, High Sheriff of the County of London 1932–1933 William Wedgwood Benn, 1st Viscount Stansgate (1877–1960), Liberal and Labour MP, and later peer. Son of John. Daniel Holmes (1863–1955), Liberal MP 1911–1918. Father-in-law of William. Tony Benn, disclaimed 2nd Viscount Stansgate (1925–2014), Labour MP for Bristol South East 1950–1960; 1963–1983 and Chesterfield 1984–2001. Son of William. Stephen Benn, 3rd Viscount Stansgate, Member of the Inner London Education Authority 1986–1990. First son of Tony. Hon. Emily Benn (born 1989), Labour Westminster candidate for East Worthing and Shoreham in 2010 and for Croydon South in 2015; Croydon London Borough Councillor 2014–2016. Daughter of Stephen. Hilary Benn (born 1953), Labour MP for Leeds Central. Second son of Tony.

Benyons Sir Henry Benyon, 1st Bt (1884–1959), High Sheriff of Berkshire 1925, Lord Lieutenant of Berkshire 1945–1959, Berkshire County Councillor. Bill Benyon (1930–2014), MP 1970–1992. Henry's second cousin, who inherited Englefield House from him upon his death, was Bill's father. Richard Benyon (born 1960), MP 2005–2019. Son of Bill.

Beresfords John Beresford, MP 1801–05 John Claudius Beresford, MP 1801–11. Son of John.

Bernal(-Osborne) Ralph Bernal, MP 1818–52 Ralph Bernal Osborne, MP 1841–74. Son of Ralph.

Bevan and Lee Aneurin Bevan, MP for Ebbw Vale 1929–1960 Jennie Lee, MP for North Lanarkshire 1929–1931 and Cannock 1945–1970. Spouse of Aneurin.

Billinghams and Skinners Angela Billingham, Baroness Billingham, Labour life peer Dennis Skinner, Labour MP; father-in-law of Angela's daughter

Bilsons Sir Thomas Bilson (1592 – ), MP for Winchester 1614. Leonard Bilson (1616–1695), MP for Petersfield 1667–1681. Son of Sir Thomas. Thomas Bilson (1655–1692), MP for Petersfield 1685–1690. Son of Leonard. Leonard Bilson (1681–1715), MP for Petersfield 1704–1715 Son of Thomas.

Blackburnes John Blackburne (1754–1833), MP 1801–31 John Ireland Blackburne (1783–1874), MP 1807–47. Son of John.

Blakes Judith Blake, Baroness Blake of Leeds, Labour Life Peer, 2021–present. Olivia Blake, Labour MP, 2019–present. Daughter of Judith.

Blennerhassetts John de Blennerhassett (1350–1384), MP for Carlisle (1381 and 1384) John Blennerhassett (died 1573), MP for Norwich (1563 and 1671) and Horsham (1558) Thomas Blennerhassett (1584–1611), MP for Carlisle (1584, 1586 and 1604) Sir John Blennerhassett (died 1624), Chief Baron of the Irish Exchequer (1621) and MP for Belfast John Blennerhassett (died 1677), High Sheriff of Kerry (1658), MP for Tralee (1661) John Blennerhassett (died 1709), MP for Tralee (1692), Dingle (1695–1699) and Kerry (1703–1709), son of the above John Blennerhassett (1691–1775), MP for Kerry (1709–1713, 1715–1727 and 1760–1775) and Tralee (1713–1715 and 1727–1760), son of the above Arthur Blennerhassett (1719–1799), MP for Tralee (1743–1761) and Kerry (1775–1783), son of the above John Blennerhassett (1715–1763), High Sheriff of Kerry (1740) and MP for Kerry (1751–1761 and 1762–1763) Robert Blennerhassett (1652–1712), MP for Clonmel (1692 and 1695) and Limerick (1703) Arthur Blennerhassett (1687–1758), MP for Tralee (1727–1758), son of the above Robert Blennerhassett (died 1689), MP for Tralee (1674), High Sheriff of Kerry (1682) Conway Blennerhassett (1693–1724), MP for Tralee (1723–1725), grandson of the above Sir Rowland Blennerhassett, 4th Baronet (1839–1909), Liberal MP for Galway Borough (1865–1874) and Kerry (1880–1885), great-great-great-nephew of the above. John Blennerhassett (1769–1794), MP for Kerry (1790–1794) Arthur Blennerhassett (1799–1843), High Sheriff of Kerry (1821) and MP for Kerry (1837–1841) Rowland Ponsonby Blennerhassett (1850–1913), MP for Kerry (1872–1885), grandson of the above John Blennerhassett (1930–2013), Fine Gael member of the Seanad Éireann (1973–1982)

Blomfield and McAvan Paul Blomfield MP Linda McAvan MEP

Boles Sir Dennis Boles, 1st Baronet (1861–1935), MP 1911–1921. Dennis Boles (1885–1958), MP 1939–1951. Nephew of Dennis. Jack Boles (1925–2013), High Sheriff of Devon 1993–1994. Nick Boles (1965–), MP 2010–2019. Son of Jack and great-nephew of Dennis.

Borwicks Robert Borwick, 1st Baron Borwick, peer Jamie Borwick, 5th Baron Borwick, excepted peer. Great-grandson of Robert. Victoria Borwick MP and Deputy Mayor of London. Spouse of Jamie.

Boswells Tim Boswell (1942–), Conservative MP 1987–2010. Victoria Prentis (1971–), Conservative MP 2015–. Daughter of Tim.