The Night action of 1/2 December 1917 during the First World War, was a local operation on the Western Front, in Belgium at the Ypres Salient. The action was a British Fourth Army (re-named from the Second Army on 8 November) attack on the German 4th Army. The Third Battle of Ypres (31 July – 10 November) proper had ended officially on 20 November but the attack was intended to capture the heads of valleys leading eastwards from the ridge, to gain observation over German positions.