| Honorific-Prefix: | The Most Honourable |
| The Marquess of Ailesbury | |
| Honorific-Suffix: | PC |
| Order1: | Vice-Chamberlain of the Household |
| Term Start1: | 7 September 1841 |
| Term End1: | 29 June 1846 |
| Monarch1: | Victoria |
| Primeminister1: | Sir Robert Peel, Bt |
| Predecessor1: | Earl of Belfast |
| Successor1: | Lord Edward Howard |
| Term Start2: | 30 December 1852 |
| Term End2: | 21 February 1858 |
| Monarch2: | Victoria |
| Primeminister2: | The Earl of Aberdeen The Viscount Palmerston |
| Predecessor2: | Viscount Newport |
| Successor2: | Viscount Newport |
| Birth Date: | 8 January 1811 |
| Birth Place: | St James's Square, London, England |
| Death Place: | Savernake, Wiltshire, England |
| Nationality: | British |
| Alma Mater: | Trinity College, Cambridge |
| Children: | 7 |
| Parents: | Charles Brudenell-Bruce, 1st Marquess of Ailesbury Hon. Henrietta Maria Hill |
Ernest Augustus Charles Brudenell-Bruce, 3rd Marquess of Ailesbury, (8 January 1811 – 18 October 1886), styled Lord Ernest Bruce from 1821 until 1878, was a British courtier and politician. He served for many years as Vice-Chamberlain of the Household.
Brudenell-Bruce was born at Warren's Hotel, St James's Square, London, the second son of Charles Brudenell-Bruce, 1st Marquess of Ailesbury, by his wife Hon. Henrietta Maria Hill, daughter of Noel Hill, 1st Baron Berwick. George Brudenell-Bruce, 2nd Marquess of Ailesbury was his elder brother and Lord Charles Bruce his younger half-brother.[1] He was educated at Eton College and Trinity College, Cambridge.[1]
He owned 55,000 acres in Wiltshire, Yorkshire and Berkshire.[2]
Brudenell-Bruce was returned to Parliament for Marlborough in 1832. He was a Lord of the Bedchamber to William IV from 1834 to 1835. In 1841 he was sworn of the Privy Council and appointed Vice-Chamberlain of the Household under Sir Robert Peel, a post he held until the government fell in 1846. He returned to the same office in December 1852 in Lord Aberdeen's coalition government. He continued in the post also when Lord Palmerston became prime minister in 1855, finally resigning in 1858. He remained MP for Marlborough until 1878, when he succeeded his elder brother in the marquessate and entered the House of Lords. In 1884 he was made Lord-Lieutenant of Berkshire, a post he held until his death two years later.
Lord Ailesbury married Hon. Louisa Elizabeth Horsley Beresford (1814–1891), second daughter of John Beresford, 2nd Baron Decies, on 25 November 1834. They had seven children:
Lord Ailesbury died at Tottenham House, Savernake, Wiltshire, in October 1886, aged 75, and was buried at Great Bedwyn, Wiltshire. His grandson George succeeded to the marquessate. The Marchioness of Ailesbury died in October 1891, aged 77, and was also buried at Great Bedwyn.[1]