Andrew Cavendish, 11th Duke of Devonshire

Andrew Robert Buxton Cavendish, 11th Duke of Devonshire, (2 January 1920 – 3 May 2004), styled Lord Andrew Cavendish until 1944 and Marquess of Hartington from 1944 to 1950, was a British peer and politician.

He was a minister in the government of Prime Minister Harold Macmillan (his uncle by marriage), and is also known for opening Chatsworth House to the public.

In 1941, the then Lord Andrew Cavendish married The Honourable Deborah Freeman-Mitford (31 March 1920 – 24 September 2014), youngest daughter of David Freeman-Mitford, 2nd Baron Redesdale and one of the Mitford sisters, in the Priory Church of St Bartholomew-the-Great, Smithfield, London.

Four of the couple's seven children died soon after birth, and the Duke's extramarital affairs became public after he appeared as a witness at a burglary trial and was forced to admit, under oath, that he was on holiday with one of a series of younger women when the crime occurred at his London home.

The Duke, however, claimed that much of his marriage's success was due to the Duchess's tolerance and broadmindedness.

The Duchess, as chatelaine, was largely responsible for the success of Chatsworth as a commercial endeavour.

Devonshire and his wife had seven children, three of whom died in infancy.

Having attended an Officer Cadet Training Unit, he was commissioned into the Coldstream Guards as a second lieutenant on 2 November 1940.

On 7 December 1944, while holding the rank of acting captain, he was awarded the Military Cross 'in recognition of gallant and distinguished services in Italy'.

The action took place on 27 July 1944 when his company was cut off for 36 hours in heavy combat near Strada, Italy.

He held the rank of major at the end of the war.

In later life, he took on a number of honorary positions within the military.

Cavendish, now styled as Marquess of Hartington, ran unsuccessfully as a National Liberal candidate for Chesterfield in the 1945 general election and as a Conservative for the same seat in 1950.

In December 1946, the Duchess had a miscarriage; had the child been born, it would have been a twin of Victor Cavendish, born in 1947.

Devonshire's older brother William, Marquess of Hartington, who would have inherited the dukedom, was killed in combat near the end of the Second World War.

He succeeded as 11th Duke of Devonshire in November 1950, and served as Mayor of Buxton from 1952 to 1954.

On 2 December 1953, he was appointed Honorary Colonel of a Territorial Army unit of the Royal Regiment of Artillery.

Devonshire served as Parliamentary Under-Secretary for Commonwealth Relations from 1960 to 1962, Minister of State at the Commonwealth Relations Office from 1962 to 1963, and for Colonial Affairs from 1963 to 1964.

He once said that these appointments by his uncle, Harold Macmillan, the then-prime minister, were "the greatest act of nepotism ever".

The duke followed the family tradition of owning racehorses, the most famous of which was Park Top, the subject of the duke's first published book, A Romance of The Turf: Park Top, which was published in 1976.

On 2 October 1981, he was appointed Honorary Colonel of the Manchester and Salford Universities Officers' Training Corps.

He joined the Social Democratic Party (SDP) in early 1982, having contacted the party's leader Roy Jenkins directly to offer his support soon after the Warrington by-election the previous summer.

He relinquished this appointment on 2 January 1985.

Latterly a supporter of David Owen – whom he later described as "the best of them" – Devonshire chose to remain with the rump 'continuing' SDP after the majority of the party's members voted to merge with the Liberal Party in 1988.

He later sat as a crossbencher during his rare appearances in the House of Lords.

Eventually though, in 1991, he signed an agreement with the Peak National Park Authority opening 1,300 acres (5 km2) of his estate to walkers.

He said that everyone was "welcome in my back garden".

The duke's real estate holdings were vast.

In addition to Chatsworth he also owned Lismore Castle in Ireland and Bolton Abbey in North Yorkshire.

He also owned the bookshop Heywood Hill and the gentleman's club Pratt's.

Devonshire was a major collector of contemporary British art, known especially for his patronage of Lucian Freud.

He was one of the founders, and the chief patron of, the Next Century Foundation, in which capacity he hosted the private Chatsworth talks between representatives of the governments of the Arab world and Israel.

His autobiography, Accidents of Fortune, was published just before his death in 2004.

The duke had many disputes over the years with the ramblers who used the paths near Chatsworth.

The duke was listed at number 73 in the Sunday Times Rich List of the richest people in Great Britain in 2004.

Cavendish was the second son of Edward Cavendish, 10th Duke of Devonshire and Mary Cavendish, Duchess of Devonshire, the former Mary Alice Gascoyne-Cecil, daughter of James Gascoyne-Cecil, 4th Marquess of Salisbury.

He was educated at Ludgrove School, Eton College and Trinity College, Cambridge.

Growing up, his elder brother, William Cavendish, Marquess of Hartington, was the heir apparent to the dukedom.

Cavendish served in the British Army during World War II.

The three surviving children were a son, Peregrine Cavendish, 12th Duke of Devonshire, and two daughters, Lady Emma Cavendish and Lady Sophia Topley.