On New Year’s Day 1917 Carrington noted in her diary that her portrait of Lytton Strachey was finished; knowing her achievement, she hugged it to herself. ‘I should like to go on always painting you every week, wasting the afternoon loitering, and never, never, showing you what I paint . . .’ Today her loving tribute is on display in the National Portrait Gallery – an exception for this ambitious yet secretive painter, whose work rarely appears in public collections.