Five days before the Armistice, Lavery wrote to Lady Jackson advising her that he could start her portrait at the end of January 1919, and indicating that his fee for a canvas approximately 50 x 40 ins would be 750 guineas. The artist confirmed that if his sitter was dressed in black and also wearing furs, these would be 'less subject to the changes of fashion' (letter dated 6 November 1918). The picture was essentially completed and paid for by the time of Lavery's departure for North Africa the following November. He intended to be away for at least five months, staying part of the time at Baron d'Erlanger's house at Sidi-bu-Said. Final retouching and varnishing would follow when the paint had dried thoroughly, after his return. Completion may however have been further delayed by the sudden death in December 1919 of the sitter's husband, Sir John Jackson MP.
Born in London, Ellen Julia Myers married the distinguished Victorian civil engineer, John Jackson in 1876. They had five daughters. Jackson trained at Edinburgh University and worked on the Tyne for a number of years before gaining renown as a dock, dam and canal builder - projects which took him all over the Empire and included Spain and South America. He was knighted in 1896 when his company completed the Manchester Ship Canal. Latterly Jackson was Unionist Member of Parliament from 1910 to 1918, for the constituency of Devenport, where he had extended the naval dockyard.