During World War II Stephenson made a series of small studies as preparation for larger works (materials being in short supply), which were executed later (in the 1950's). They were stimulated by the devastation resulting from the bombing of London (also recorded figuratively by Stephenson during this period). Stephenson made his first abstract paintings around 1932. In 1934 he exhibited with the 7 & 5 Society, along with Ben and Winifred Nicholson, Ivon Hitchens, Henry Moore, Barbara Hepworth and John Piper. Though not today as well known as many of his contemporaries he was one of the key figures in the development of abstract art in Britain in the mid twentieth century.