Leonard Gordon Duke (1890–1971), a civil servant and colleague of Paul Oppé (1878–1957) at the Board of Education, built up a substantial collection of British watercolours and drawings in the middle of the twentieth century. These included fifteen drawings by or attributed to Girtin. The manuscript catalogue of his collection is in the Department of Prints and Drawings at the British Museum. Duke sold or gave away many drawings during his lifetime; what remained of his collection, amounting to 1,351 lots, was disposed of in seven sales at Sotheby’s in 1970–71, just before his death (Exhibitions: Sotheby's, 5 March 1970; Sotheby's, 16 July 1970; Sotheby’s, 29 April 1971).