The extension was begun by French troops in October 1914 and when they moved south in March 1916 to be replaced by Commonwealth forces, it was used for burials by the 6th Casualty Clearing Station. In November 1917, Barlin began to be shelled and the hospital was moved back to Ruitz, but the extension was used again in March and April 1918 during the German advance on this front. The extension contains 1,095 Commonwealth burials of the First World War, including Charles Throsby from Greetham. There are also 63 French and 13 German burials. The extension was designed by Sir Edwin Lutyens.