At the start of World War One, Lamb returned to his medical studies and qualified as a doctor at Guy's Hospital.
Lamb saw active service in the First World War in the Royal Army Medical Corps as a battalion medical officer with the 5th Battalion, The Royal Inniskilling Fusiliers and was awarded the Military Cross.
 Lamb served in Palestine and on the Western Front and was badly gassed not long before the end of the war.
In February 1918, before he was demobilised, Lamb was approached by British War Memorials Committee of the Ministry of Information to produce a large painting for a proposed national Hall of Remembrance.
After he was demobilised in March 1919, Lamb began work on the painting, Irish Troops in the Judaean Hills Surprised by a Turkish Bombardment, which is now in the Imperial War Museum.
At the start of World War One, Lamb returned to his medical studies and qualified as a doctor at Guy's Hospital. Lamb saw active service in the First World War in the Royal Army Medical Corps as a battalion medical officer with the 5th Battalion, The Royal Inniskilling Fusiliers and was awarded the Military Cross.  Lamb served in Palestine and on the Western Front and was badly gassed not long before the end of the war. In February 1918, before he was demobilised, Lamb was approached by British War Memorials Committee of the Ministry of Information to produce a large painting for a proposed national Hall of Remembrance. After he was demobilised in March 1919, Lamb began work on the painting, Irish Troops in the Judaean Hills Surprised by a Turkish Bombardment, which is now in the Imperial War Museum.
Henry Lamb