Magniac was the eldest son of Hollingworth Magniac of Colworth, Bedfordshire. Following education at Eton College and the University of Cambridge, he worked in finance in the City of London, becoming a partner in Matheson and Company of Lombard Street. He was appointed a deputy lieutenant for the City, and was the first president of the London Chamber of Commerce. In about 1869 Magniac purchased Chesterfield House the great Mayfair townhouse built 1747-52 by Philip Stanhope, 4th Earl of Chesterfield, which had been threatened with demolition.
Magniac was a committed Liberal, and was elected as a member of parliament for the party on a number of occasions. He was first elected as an MP in 1868, representing St Ives, Cornwall. A contemporary political reporter commented:
"St Ives, (Cornwall) scared away Mr Paull (C), and embraced Mr. Magniac (L), of the firm of Matheson & Co., the frightfully rich China merchants in the City, who when they lose a quarter of a million [pounds] are no more concerned about it than I should be if I were to lose half a crown."
He held the St Ives seat until 1874 then returned to the House of Commons in 1880, as one of two MPs for the Borough of Bedford. In 1885 the constituency's representation was reduced to one member, and Magniac was selected as Liberal candidate for the new Northern or Biggleswade Division of Bedfordshire. He was elected at the 1885 general election, but was defeated in the following election in 1886. He was chosen as Liberal candidate for the next general election, but died before it took place.
Magniac was also deeply interested in agriculture, and was a breeder of shorthorn cattle and carthorses.
In 1857 Magniac married Augusta Dawson (?–24 February 1903, née, FitzPatrick), daughter of Baron Castletown, and widow of Lieutenant-Colonel Thomas Vesey Dawson, who died in action at the Battle of Inkerman in 1854. Their daughter, Helen Augusta, married the army officer and explorer Francis Younghusband, to whom her brother, Vernon, served as private secretary on the British expedition to Tibet in 1904.
Magniac died suddenly at his London residence in November 1891. At the time of his death he was chairman of Bedfordshire County Council, as well as a justice of the peace and deputy lieutenant for the county.
- "Obituary". The Times. 24 November 1891. p. 6.
- Walford, Edward. Old & New London, London, 1878, vol.4, p.354
- "The Lounger". Illustrated Times. British Newspaper Archive. 5 December 1868. Retrieved 24 July 2014. (subscription required (. ))
- "Election Intelligence". The Times. 10 January 1885. p. 6.
- L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 98.
- Fleming, Peter (2012). Bayonets to Lhasa - the British invasion of Tibet. Tauris Parke, London. ISBN 9780857731432.
- Hansard 1803–2005: contributions in Parliament by Charles Magniac
|Parliament of the United Kingdom|
|Member of Parliament for St Ives
1868 – 1874
| Succeeded by|
Edward Gershour Davenport
Frederick Charles Polhill-Turner
and Samuel Whitbread
|Member of Parliament for Bedford
1880 – 1885
With: Samuel Whitbread
| Succeeded by|
|New constituency||Member of Parliament for Bedfordshire Northern
1885 – 1886
| Succeeded by|