| Honorific Prefix: | The Honourable |
| William Cornwallis-West | |
| Honorific Suffix: | VD JP |
| Office: | Lord-Lieutenant of Denbighshire |
| Term Start: | 1872 |
| Term End: | 1917 |
| Predecessor: | Robert Myddelton Biddulph |
| Successor: | The Lord Kenyon |
| Office1: | Member of Parliament for Denbighshire West |
| Term Start1: | 1885 |
| Term End1: | 1892 |
| Predecessor1: | New constituency |
| Successor1: | John Roberts |
| Birth Name: | William Cornwallis West |
| Birth Date: | 20 March 1835 |
| Birth Place: | Florence |
| Death Place: | Ruthin Castle |
| Residence: | West Central London Newlands Manor (most summers) Ruthin Castle, Ruthin, Denbighshire (all concurrently) |
| Party: | Liberal Party |
| Education: | Eton |
| Parents: | Frederick Richard West Theresa Cornwallis Whitby |
| Children: | Daisy, Princess of Pless Constance Lewis George Cornwallis-West |
| Relatives: | Mary Anne Whitby (grandmother) |
William Cornwallis Cornwallis-West VD JP (20 March 1835 – 4 July 1917), was a British landowner, politician for seven years from 1885 and raised the 6th (Ruthin) Denbighshire Rifle Volunteer Corps followed by further ceremonial duties in the wider territorial army in Wales.
He was born William Cornwallis West. He was a son of Frederick Richard West, a Tory MP for Denbigh Boroughs and East Grinstead who was a member of the Canterbury Association and his wife who was born Theresa Whitby. His father first married Lady Georgiana Stanhope (a daughter of Philip Stanhope, 5th Earl of Chesterfield).[1]
His paternal grandfather was Frederick West (a son of John West, 2nd Earl De La Warr). His maternal grandparents were both Royal Navy figures: John Whitby and Mary Anne Theresa Symonds (heiress to the fortune of Admiral William Cornwallis).[2]
He was called to the Bar, Lincoln's Inn, in 1862.[3]
Cornwallis-West was High Sheriff of Denbighshire in 1872, Lord-Lieutenant of Denbighshire from 1872 to 1917, and a Justice of the Peace for Hampshire and Denbighshire. In 1885 he won a fought election to Parliament for Denbighshire West as a Liberal, a seat he held until 1892 latterly as a Liberal Unionist (which took an anti-Irish Home Rule line).
He lost to the Liberal Party's candidate that year as the parties began their clearer left/right split.[4] He raised the 6th (Ruthin) Denbighshire Rifle Volunteer Corps in 1861 and became commanding officer of the 1st Volunteer Battalion, Royal Welch Fusiliers in 1885. In 1890 he became Honorary Colonel of the battalion and later of its successor, the 4th (Denbighshire) Battalion, Royal Welch Fusiliers in the Territorial Force.[5]
In 1895 he assumed by deed poll the surname of Cornwallis-West. In his most active years he lived simultaneously in London, at Ruthin Castle, Denbighshire and at Newlands Manor, Milford, Hampshire.[6]
Cornwallis-West married Mary ("Patsy"), daughter of Frederick Fitzpatrick, in 1872. Born in 1856, "Patsy" was 17 years old. She was known as a great beauty and leading socialite.
Their children all endured divorce:
Cornwallis-West died in July 1917, aged 82. His widow died in July 1920, shortly after returning from Monaco, at her family's Arnewood House which has a half-wooded holding north of her other mansion: Newlands, near Milford-on-Sea in Hampshire.
Newlands Manor, Hampshire is a Grade II listed Strawberry Hill Gothic style manor house, dating from the late 18th century.
George, who had already been declared bankrupt, after the sale of certain lots, decided to dispose of the bulk - the rest - of the Hampshire estate so astutely acquired by his great-grandmother.[10]
In 1920 the estate of 2,000 acres was put up for auction in 91 lots. The mansion and its grounds and four lodges were sold in one lot. Other lots included arable, pasture and woodland, building sites in Milford, 30 cottages and farms including Batchley, Kings, Harts, Lea Green and Downton Manor.
The house, which had been badly neglected, and 500 acres was bought by Sir John Power, MP for Wimbledon, who made improvements but put it up for sale in 1948. The house and 38 acres were then acquired by a developer who turned it into six flats.[10] As of 2023, the house was on sale for an estimated £3 million.[11]