According to the National Maritime Museum, John Kingsley Cook served in the merchant navy during WW II. He joined in 1940 as a wireless officer, and went on his first sea voyage in December that year. His ship was sunk off the coast of Algeria in 1941 and the survivors were taken captive and held until liberated the following year after the Allied landing in North Africa
He resumed service after a few months during which time he visited Gibraltar and produced a series of watercolours some of which are shown below. Cook used the backs of obsolete navigational charts for most of his paintings including those he did of Gibraltar.
John Kingsley Cook - Shortly before he made this self-portrait, on a day’s leave on shore, an unfortunate tennis accident gave him a black eye: perhaps this is why half his face is left in the shadow
The Rock
Gibraltar Harbour tugs, the Energetic and the Rambler
Soldiers seem to be marcching down the road from Buena Vista Barracks
The Rock's Searchlights on the 7th of June 1944
Entering Gibraltar Harbour
View from the deck
Convoy leaving Gibraltar
Cleaning the guns of the Esturia with the town of Gibraltar in the background
Gibraltar Harbour tugs, the Energetic and the Rambler
Soldiers seem to be marcching down the road from Buena Vista Barracks
The Rock's Searchlights on the 7th of June 1944
Entering Gibraltar Harbour
View from the deck
Convoy leaving Gibraltar
Cleaning the guns of the Esturia with the town of Gibraltar in the background