Joseph's best known poem, "Warning", was written in 1961 when she was 28. First published in
The Listener in 1962, "Warning" was later included in her 1974 collection
Rose In the Afternoon, in
The Oxford Book of Twentieth Century English Verse, and in her
Selected Poems (1992). The poem became well known in America after
Liz Carpenter (formerly the first woman executive assistant to Vice President
Lyndon Baines Johnson and Press Secretary to former First Lady
Lady Bird Johnson), wrote an article for the ''
Reader's Digest'' in the early 1980s, about enjoying life having recovered from an illness, closing the article with "Warning". The poem was adopted by the greeting-card industry, led by graphic designer and calligrapher Elizabeth Lucas. Joseph ascribed the popularity of the poem to Lucas. "To her business acumen and energy I owe a hospitable following in California and later throughout northern America, more social, as I said, than literary. "Warning" was identified as the UK's "most popular post-war poem" in a 1996 poll by the
BBC. The opening lines "When I am an old woman I shall wear purple, With a red hat which doesn't go, and doesn't suit me" were the inspiration for the
Red Hat Society. Due to its popularity, an illustrated gift edition of "Warning", first published by
Souvenir Press Ltd in 1997, has now been reprinted 41 times. "Warning" was included in the anthology
Tools of the Trade: Poems for new doctors (Scottish Poetry Library, 2014) and a copy was given to all graduating doctors in Scotland in 2014. Joseph herself hated the colour purple, which is why she included it in the poem. == Personal life ==