She already knew him by sight, having observed him years before from the church congregation.

Isobel Lucas was born in Chelsea, London on 15 May 1904. Her early childhood was characterised by a contrast between the strict education of the London French Convent and the liberal atmosphere of the home of her uncle, William Arthur Jones, editor of the Weekly Times. At the age of seven, she moved with her family to Kew. However, three years later, on the outbreak of the First World War, Isobel’s parents moved again, to Broadstairs, Kent, and Isobel was sent to a boarding convent at Blundell Sands on Liverpool Bay. After another three years, she was educated privately in Broadstairs. On finishing her general education, she attended the Margate and Ramsgate Art School before moving to the Central School in London.

At the Central School of Art, John and Isobel received a thorough grounding in contemporary book production under A S Hartrick and G Spencer Pryse. By the time of their engagement, they had developed complementary artistic approaches, so that when they graduated, and married, in 1924, their talents fitted hand in glove. A large number of their future projects took the form of collaborations, beginning in 1936 with The Yellow Cat by Mary Griggs. In the same year they were introduced by Sir Robin Lusty of the publisher Michael Joseph to Eleanor Farjeon as the perfect choice of illustrator for her latest book, Martin Pippin in the Daisy Field (1937). Its success made them central members of the Farjeon circle.

In the belief that they had fostered sufficient contacts with publishers and writers, the Morton-Sales moved in 1937 to an ancient and remote house on the edge of Dartmoor. In retreating from the commercial and social world that supported them, they transferred the developing romanticism of their art to their lives. During the Second World War, their place and their projects provided timeless ideals to compensate for the ravages of history. However, John did produce a system of camouflage that was adopted for use and, after the war, engaged with the metropolitan art world by contributing to exhibitions at the Leicester Galleries.

In 1952, the Morton-Sales founded and directed the Parnassus Gallery, based at barns at Slocombe. For many years they published reproductions of their own paintings and works by established masters, often little-known masterpieces that they had discovered for themselves. John had a keen eye for judging the form and colour of both the original objects and their reproduction. Eleanor was praised for her concise and vivid accompanying descriptions. The Parnassus publications made a rare and lasting contribution to the dissemination of the fine arts. In 1977, the Morton-Sales retired from the Parnassus Gallery, but even then continued to draw and paint. In 1984, they shared a painting retrospective at the Maas Gallery, London. Though John was unable to attend the opening, he took pleasure in seeing it hung. He died at Chagford, Devon on 14 March 1990. Isobel died two years later, at Moretonhampstead on 25 November 1992.

A major retrospective exhibition of the work of John & Isobel Morton-Sale was mounted at Chris Beetles Gallery in 1996. It was accompanied by a full-colour catalogue with a biographical essay and a bibliography.