Susana (née Susana Valeria Rosa Maria Gil Passo) was born in Argentina, the daughter of a lawyer who ensured that all this children learned English, so she grew up bilingual and graduated with diplomas in accountancy and translation. Her first job was with the British Council in Buenos Aires.

Susana first met William Walton in 1949 in Buenos Aires when Walton was attending an international meeting of the Performing Right Society, and at which Susana was working for the British Council delegate. Walton turned to her and said “You will be very surprised, Miss Gil, to hear that I am going to marry you!” She rejected his proposal for three weeks until just before his return to England, by which time he’d given up, no doubt discouraged. She suggested he try one more time: he did and she accepted. 

After their marriage the Waltons moved to the island of Ischia in the Bay of Naples and settled in a house called La Mortella, around which Lady Walton and the landscape architect Russell Page created what has become a world-famous garden. It was opened to the public in 1992 and each year welcomed thousands of visitors. Under the auspices of the Fondazione William Walton e La Mortella she hosted masterclasses and concerts on the garden. She also had constructed a greek theatre large enough to accommodate an orchestra where symphonic and operatic performances are given each summer.

In March 1990 she recorded her husband’s Façade, alongside Richard Baker, with Richard Hickox conducting the City of London Sinfonia for Chandos. In his April 1991 review Alan Blyth commented on “how well she understands the idiom and how much vocal presence she gives to her reciting”. Four years later she attended the Gramophone Awards to collect the Opera Award, with Richard Hickox, for Walton's opera Troilus and Cressida, recorded as part of Chandos's Walton Edition (see photo). 

In 2001 Lady Walton was awarded an honorary doctorate by the University of Nottingham in recognition of her work in maintaining the legacy of her husband, and in 2002 she received an MBE. She is the author of two books: Behind the Façade, a biography of Sir William Walton, and La Mortella – an Italian Garden Paradise, a history of her garden at La Mortella.

After Walton’s death in 1983 his ashes were housed in a pyramid rock, “William’s Rock”, in the Upper Garden, and on Thursday following a private cremation in Naples the day before, Susana’s ashes will be placed in the Nymphaeum she created nearby.