Christopher is Chairman of the Furniture History Society and a member of the Reviewing Committee on the Export of Works of Art and Objects of Cultural Interest (RCEWA). He was appointed to the curatorial staff of the National Trust in 1977, working first in the West Midlands and Wales before moving to the South-East of England in 1986. He was co-curator of the exhibition Turner at Petworth in 2002, held in partnership with Tate, and was co-author of the exhibition catalogue. He was the National Trust’s Curator of Furniture (2002-21) and has published widely, with the focus on historic house collections, including furniture, paintings, picture frames and sculpture (e.g. Grinling Gibbons at Petworth). He edited and was the principal contributor to Ham House: 400 Years of Collecting and Patronage (Yale University Press, New Haven and London, 2013). His histories of the display and exhibition of art (including sculpture) were published in The Grove Dictionary of Art (1996)/ Oxford Art Online/Grove Art Online (2003).