She is a specialist in modern British art and the author of a centenary history of the Tate. She has also written several biographies, mostly on artists, including Vanessa Bell, Gwen Raverat, John Minton, Duncan Grant and on the poet and novelist Stevie Smith. In 2014 she guest-curated for the National Portrait Gallery the exhibition, Virginia  Woolf: Art, Life and Vision, and wrote the accompanying book with the same title. She taught for 15 years at Newcastle University, becoming Professor of Art History, and left to become  Editor of the Burlington Magazine  for one year. Currently Emeritus Fellow at Clare Hall, University of  Cambridge. She is  also a FRSL, Hon.FRCA and was awarded CBE for services to literature in 2005.

She recently wrote the  Foreword to  Comrades in Art: Artists against Fascism 1933-1943,  by Andy Friend, to be published by Thames & Hudson in September of this year. It tracks the history of the AIA (Artists International Association). Each shift in its development is tied into the historical moment, with expert grasp of the tensions behind the world crises that lead to another world war.  The blurb advises: ‘The Rise of the far right and authoritarianism in our own time makes this book vital reading for everybody concerned with visual culture.’