Artist traces Manchester’s links to slavery on blue cotton gown

Artist Holly Graham collaborated with her mother, the stage and screen costumier Jennifer Graham, and researchers to create the dress. Photograph: Christopher Thomond/The Guardian

For nearly 160 years, the blue plaque has marked sites of historic importance. Now one English institution has found its own way of signifying a flagship moment while interrogating its past – a blue dress.

The new artwork, at Manchester Art Gallery, commemorates the occasion when the African American abolitionist Sarah Parker Remond made a speech on the site in 1859.