Penelope Loader, Lady Aitken, MBE (2 December 1910 – 7 February 2005), styled The Honorable Lady Aitken and nicknamed 'Pempe', was an English socialite.
Born Penelope Loader Maffey, she was the daughter of Sir John Maffey, later 1st Baron Rugby, who was to become Governor-General of the Sudan, Permanent Secretary of the Colonial Office and wartime Ambassador to Dublin. Earlier, he had been the private secretary to the Viceroy of India and Governor of the North-West Frontier Province, thus Penelope was born in Peshawar and spent her early years in India, where three of her siblings died in childhood.
When she was seven years old, she returned to England for prep school, then went on to Sherborne School for Girls. Her parents had a house, Anmer Hall, on the King's Sandringham estate, which led to her socialising with the royal family. Indeed, she became the King's favourite. Maffey was presented at Court and named Debutante of the Year. Strikingly beautiful, she was romantically linked with several men, including Prince Bernhard of Lippe-Biesterfeld (later Prince Bernhard of the Netherlands), Esmond Harmsworth and society artist Simon Elwes (1902–1975), which caused a minor scandal as he was married and a Roman Catholic. Maintaining a platonic friendship, she accompanied Prince Bernhard on his honeymoon in 1937 and became good friends with his new wife, Princess Juliana of the Netherlands.