On the outbreak of War, he abandoned his young accountancy practice and enlisted in the Inns of Court Officer Training Corp, in which he was made Sergeant owing to his knowledge of drill acquired during many years attendance at Public School Camps and as an officer of the Jewish Lads' Brigade.

He joined his regiment on active service on the Western Front in March 1916, and soon attracted the favourable attention of his superior officers. One of his earliest written reports of service on patrol was read out in orders as a model of efficiency. On the 7th of August, he was appointed to the acting rank of Captain.

In the early morning of the 3rd of September, he was in command of one of three companies which made an attack on German trenches "immediately North of the river Ancre and the village of Thiepvaal." He was reported by the War Office as among he missing but though no precise information was available (he had at the outset told his men "they were to press on to their objectives no matter whether he or anyone else was hit") the evidence of those who returned from the raid established beyond reasonable doubt that Ernest had met an almost instantaneous death.

In his last letter, dated shortly before the raid, which he left to be delivered to his Mother and Father in case he fell, he had written, "I only pray that I may meet my end as an Englishman and a Jew should. I have always been proud to have been both."

From his early manhood, Ernest was deeply interested in social work among youths of the East End of London. He was devoted to the work of the Jewish Lads' Brigade of which he was a particularly active officer. Before leaving for the Front, he had expressed the hope that if he fell his family would take an interest in the movements for which he had worked.

Gifts in his memory were consequently made by his parents, brothers and sisters to the following, among other Associations and Philanthropic bodies: - The Jewish Athletic Association, St George's Jewish Settlement, The Jewish Lads' Brigade, Brady Street Club, Lady Lansdowne's Officers Fund. A sum of money was also invested in a trust for his godson Ernest, son of his Batman, William Hallett, who also fell in the same engagement.

Ernest wrote a total of 67 letters home to his family, which have been recorded and scanned. There are a few examples in this personal record but a history window will be created with them soon.