William Ponsonby, 1st Baron de Mauley

William Francis Spencer Ponsonby, 1st Baron de Mauley (31 July 1787 – 16 May 1855), was an English Whig and Liberal politician who sat in the House of Commons between 1826 and 1837. He was raised to the Peerage in 1838.


Ponsonby was the youngest child of 3rd Earl of Bessborough and his wife Henrietta Ponsonby, Countess of Bessborough.[1]

Ponsonby was elected Member of Parliament for Poole in 1826 and held the seat until 1831, when he lost it in a by-election to Lord Ashley.[2][3] He was then MP for Knaresborough between June and December 1832.[4] At the 1832 UK general election he was elected MP for Dorset and held the seat until 1837.[5] In 1838 he was created Baron de Mauley. Whilst an MP for Poole, Ponsonby and Benjamin Lester opened Poole's first public library in 1830.[3]

When the marriage of his sister Lady Caroline to William Lamb, 2nd Viscount Melbourne, began to break up, he strongly supported Caroline.[6] Unfortunately he was not noted for tact or intelligence—Melbourne's sister Emily Lamb, Countess Cowper, described him as being universally regarded as "an ass and a jackanapes".[6] Ponsonby reminded Melbourne that the Lamb family were socially parvenu, and that his sister had married beneath her; although arguably true, these remarks were so tactless that Melbourne broke off any further dealings with him.[6]


On 8 August 1814, Ponsonby married Lady Barbara Ashley-Cooper (the only daughter and heir of the 5th Earl of Shaftesbury and a co-heir of the medieval Barony of Mauley, 1789–1844). They had three children:[1]


  1. ^ a b Burke, John Bernard (1845). A Genealogical and Heraldic Dictionary of the Peerage and Baronetage of the British Empire. H. Colburn. p. 284. Retrieved 15 October 2016.
  2. ^ Leigh Rayment's Historical List of MPs – Constituencies beginning with "P" (part 2)
  3. ^ a b Legg, Rodney (2005). The Book of Poole: Harbour and Town. Halsgrove. p. 55. ISBN 1841144118.
  4. ^ Leigh Rayment's Historical List of MPs – Constituencies beginning with "K" (part 2)
  5. ^ Leigh Rayment's Historical List of MPs – Constituencies beginning with "D" (part 2)
  6. ^ a b c Lord David Cecil, Melbourne, Pan Books edition 1965, p. 151.

External linksEdit

Parliament of the United Kingdom
Preceded by
Benjamin Lester
John Dent
Member of Parliament for Poole
With: Benjamin Lester
Succeeded by
Benjamin Lester
Sir John Byng
Preceded by
Hon. Henry Cavendish
George Tierney
Member of Parliament for Knaresborough
June–December 1832
With: Hon. Henry Cavendish
Succeeded by
John Richards
Benjamin Rotch
Preceded by
Edward Portman
Lord Ashley
Member of Parliament for Dorset
Served alongside: Lord Ashley
William Bankes to 1835
Henry Sturt from 1835
Succeeded by
Lord Ashley
John Fox-Strangways
Henry Sturt
Peerage of the United Kingdom
New creation Baron de Mauley
Succeeded by
Charles Ponsonby