Born on 2 May 1902, the son of Captain Robert Stevenson Dalton Cuming, CBE, DSO, Royal Navy and Mrs Henrietta Florence Cuming (née Gibson-Craig), Robert Cuming was educated at a preparatory school in Horsham.

He joined the Royal Navy as a Cadet at the Royal Naval College, Osborne, in January 1916.  Promoted to Midshipman on 15 September 1919, he joined the battlecruiser, HMS REVENGE for sea training.  Promotion to Acting Sub Lieutenant followed on 15 January 1922 before appointment to the Royal Naval College at Greenwich for Sub Lieutenants’ Courses on 15 April.  These were followed by an appointment to HMS DOLPHIN (Submarine School) for submarine training on 29 July.  He was then appointed to the Submarine Flotilla Leader HMS CONQUEST (1st Submarine Flotilla) for HMS K22 as Navigating Officer, his first operational boat.  On 13 November 1924, he was severely reprimanded by sentence of a Court Martial for allowing K22 to be stranded.

Promotion to Lieutenant followed on 15 July 1924.  Robert Cuming was next appointed to the Submarine Depot Ship HMS VULCAN (6th Submarine Flotilla) at Portland for Submarine H44 as First Lieutenant on 3 September 1925. He returned to the surface navy on 29 December 1926 when appointed to the destroyer, HMS WALPOLE (6th Destroyer Flotilla), in the Atlantic Fleet.

Robert Cuming inherited the Riccarton Estate (near Edinburgh) on 5 September 1926 from his uncle, Sir Henry Gibson-Craig and, on doing so, adopted the surname Cuming-Gibson-Craig.  On 18 December 1927 he was listed as ‘between appointments’ before joining the Submarine Tender HMS PIGMY (Reserve Half Flotilla) at Portsmouth ‘for Group M Submarines in Reserve – for HMS L14’.

Robert Cuming-Gibson-Craig was appointed to the Submarine Commanding Officers’ Qualifying Course (COQC) on 12 April 1929, and on 20 August 1929, he was appointed to the Submarine Depot Ship HMS ROSS (Experimental Half Flotilla) at Portsmouth for HMS H43 in command.

Lieutenant Robert Cuming-Gibson-Craig died on 19 February 1930.  It is understood that he had been visiting the Submarine Depot Ship HMS MEDWAY in Portsmouth Dockyard.  He left the Depot Ship by car in the company of Paymaster Lieutenant Commander Reginald Ashton.  Whilst driving through the Dockyard, the vehicle accidentally drove into No. 1 Dock.  The Paymaster Lieutenant Commander died in the accident and, although he was rescued from the bottom of the dock whilst still alive, Robert Cuming-Gibson-Craig died later in HMS MEDWAY.