Emigrating to England with his family, he was educated at Highgate School, before going up to Oriel College, Oxford to read law.
[2] He commanded a section of mounted infantry at The Battle of Zand River in June 1900, in addition to taking part in the actions at Ladybrand in September 1900 and the pursuit of Christiaan de Wet in the Orange Free State.
[1] He was appointed in April 1907 as an instructor of military law and administration to F Company at Sandhurst, a position he held until 1911.
[5] At the end of October 1914, the battalion were ordered to British India and were aboard their ship and ready to embark when at the last minute Docker was recalled by telegram to join the King's Own Royal Regiment on the Western Front.
Docker entered the trenches the following evening near Touquet in Belgium and was killed in action on the morning of 17 November.