Question: Colonel Humphrey Mews was Deputy Private Secretary to which member of the British royal family?

Context paragraphs:
Princess Alice, Countess of Athlone: Princess Alice, Countess of Athlone, (Alice Mary Victoria Augusta Pauline; née Princess Alice of Albany; 25 February 1883 – 3 January 1981) was a member of the British Royal Family.  She is the longest-lived Princess of the Blood Royal of the British Royal Family, and was the last surviving grandchild of Queen Victoria.  She also held the titles of Princess of Saxe-Coburg and Gotha and Duchess in Saxony from birth, as well as a Princess of Teck by marriage, until 1917 when the British Royal Family ceased usage of German titles.  She was godmother to Queen Beatrix of the Netherlands, who is the granddaughter of her first cousin on her mother's side, Queen Wilhelmina of the Netherlands.

Australian State Coach: The Australian State Coach is an enclosed, six horse-drawn carriage used by the British Royal Family.  The coach was presented to Queen Elizabeth II of Australia and the United Kingdom as the official gift on the occasion of the Australian Bicentennial on 8 May 1988, and first used in November of that year at the State Opening of Parliament.  The coach was a gift from the Australian people and was designed and built by the coach builder W. J. Frecklington who subsequently built the Diamond Jubilee State Coach for Queen Elizabeth II as a private initiative.  The Australian State Coach is sometimes used at the British State Opening of Parliament and other state occasions involving the Australian or foreign royal families, such as the visit of Queen Margrethe of Denmark in 2000.  As one of the most modern of the royal carriages, the coach is fitted with electric windows, heating and hydraulic stabilisers; it is therefore regularly used for such occasions.  The Australian State Coach is usually kept at the Royal Mews, where it can be viewed by the public.

Genealogy of the British royal family: The recorded genealogy of the British royal family traces back to the early Middle Ages.  Although there is no strict legal or formal definition of who is or is not a member of the royal family, and different lists will include different people, those carrying the style His or Her Majesty (HM) or His or Her Royal Highness (HRH) are generally considered members.  The current British royal family are members of the House of Windsor.

Ian Dixon Scott: Sir Ian Dixon Scott {'1': ", '2': ", '3': ", '4': "} (6 March 1909 – 3 March 2002) was a British civil servant and a career diplomat who served as Deputy Private Secretary to the last two Viceroys of India.  He was later appointed Ambassador to Congo, Sudan and Norway in the 1960s.

British royal family: The British royal family comprises the monarch of the United Kingdom and her close relations.  There is no strict legal or formal definition of who is or is not a member of the British royal family, and apart from Queen Elizabeth II herself, different lists will include different people.  Those who, at a time in question, carry the style His or Her Royal Highness (HRH), and any styled His or Her Majesty (HM), are normally considered members, including those so styled before the beginning of the current monarch's reign.  By this criterion, a list of the current royal family will usually include the monarch, the consort of the monarch, the widows of previous monarchs, the children and male-line grandchildren of the monarch and previous monarchs, the children of the eldest son of the Prince of Wales, and the wives or widows of the monarch's and previous monarchs' sons and male-line grandsons.

Charles, Prince of Wales: Charles, Prince of Wales (Charles Philip Arthur George; born 14 November 1948) is the eldest child and heir apparent of Queen Elizabeth II.  Known alternatively in Cornwall as Duke of Cornwall and in Scotland as Duke of Rothesay, he is the longest-serving heir apparent in British history, having held the position since 1952.  He is also the oldest person to be next in line to the throne since Sophia of Hanover (the heir presumptive to Queen Anne), who died in 1714 at the age of 83.

Thawisan Ladawan: Thawisan Ladawan (Thai: ทวีสันต์ ลดาวัลย์ ) (26 January 1923 – 7 April 2006) was husband of Busba Kitiyakara (younger sister of Queen Sirikit), a member of King Bhumibol Adulyadej's Privy Council, and for 26 years, principal private secretary to the King.  Thawisan attended Vajiravudh College and graduated from the inaugural class of Thammasat University in 1938.  He worked in several capitals, including Paris and Brussels, and earned a Diplome d'Etudes Superieures de Droit International Public from Paris University in 1954.  He became Deputy Director-Deneral of the Protocol Department before departing in 1968 to serve as Deputy Principal Private Secretary to Bhumibol.  A year later he became Bhumibol's Principal Private Secretary, and was later appointed to the Privy Council.  He died at the age of 83 due to chronic liver disease.

Humphrey Mews: Colonel Humphrey Mews (1941-1990) was Deputy Private Secretary to His Royal Highness the Prince of Wales 1986-1988.

Edward Young (courtier): Edward Young, CVO is the current Deputy Private Secretary to Queen Elizabeth II.  He received his promotion in September 2007 after the promotion of Christopher Geidt from Deputy Private Secretary to Private Secretary, on the retirement of Sir Robin Janvrin, former Private Secretary, 1999–2007.

Royal Mews: A Royal Mews is a mews (i.e. combined stables, carriage house and in recent times also the garage) of the British Royal Family.  In London the Royal Mews has occupied two main sites, formerly at Charing Cross, and since the 1820s at Buckingham Palace.  The site is open to the public throughout much of the year.

Supporting paragraphs: Humphrey Mews Charles, Prince of Wales
Answer: Charles, Prince of Wales