Susan Cunliffe-Lister, Baroness Masham of Ilton

Susan Cunliffe-Lister, Countess of Swinton, Baroness Masham of Ilton, DL, DSG ( née Sinclair; born (1935-04-14)14 April 1935) is a crossbench member of the House of Lords. She is the senior female life peer.

She was the daughter of Major Sir Ronald Sinclair, 8th Baronet. She was educated at the Heathfield School and London Polytechnic.

In 1959 she married Lord Masham (1937–2006), who became The 2nd Earl of Swinton in 1972. By this marriage, she became Lady Masham, and later Countess of Swinton. She was created a life peer in 1970 as the Baroness Masham of Ilton, of Masham in the North Riding of the County of York. She and her husband are one of the few couples to both hold titles in their own right.

Lord and Lady Swinton adopted two children. She was widowed in 2006.

She is a prominent Roman Catholic convert and a patron of the Margaret Beaufort Institute of Theology.

She was disabled in a riding accident in 1958, and subsequently became a champion for causes related to disability. She was the subject of This Is Your Life in February 1976 when she was surprised by Eamonn Andrews in the foyer of the De Vere hotel in Kensington, London.

She is an active member of the House of Lords, where she continues to be known as the Baroness Masham of Ilton, a title she holds in her own right. She takes a particular interest in issues surrounding disability, health and penal reform. She continues to run the Masham Riding Centre in Masham, North Yorkshire. In 2011 she was awarded an Honorary Fellowship by the Royal College of Nursing.

She competed in several Paralympic Games, winning medals for table tennis in 1960, 1964, and 1968. She is Vice President of the Snowdon Trust, founded by the Earl of Snowdon, which provides grants and scholarships for students with disabilities.

• Miss Susan Lilian Primrose Sinclair (1935 – 1959)
• Lady Masham (1959 – 1970)
• The Rt Hon. The Baroness Masham of Ilton (1970 – present) ‡
• The Rt Hon. The Countess of Swinton (1972 – 2006)
• The Rt Hon. The Dowager Countess of Swinton (2006 – present)

‡ As active member of the House of Lords, she uses in daily life her life peer title.