Duncan Grant was approached by the War Artists’ Advisory Committee in March, 1940, and agreed to undertake a commission to paint naval subjects for one pound a day, plus travelling expenses. Grant spent two weeks in Plymouth on this consignment, lodging first at the Duke of Cornwall Hotel, then in a room on The Hoe at 3 Windsor Place. It was there that he met with John Nash, now an Official War Artist, who warned Grant that spy mania was rife at the dockyards, and he would be subjected to constant interruption if he tried to paint there. So Grant instead settled on the subject of sailors having gunnery lessons in the naval barracks.

In his letters to Vanessa Bell from this period, it is clear that Grant was grateful for a glimpse into naval life. He was struck by the apparently universal belief in Churchill, and was filled with respect for the efficiency and charm of the navy. He often lunched with the Admiral, and tells a humorous anecdote about hurriedly throwing away a cigarette in the presence of the Commander-in-Chief – ‘a magnificent gentleman who was a cross between Macaulay of King’s and the Duke of Wellington’.

Wartime works by Grant are exceedingly rare, and the artist was paid 100 guineas for the finished composition from his time in Plymouth, Gun Drill, 1941 (now in the collection of the Museum of New Zealand Te Papa Tongarewa). While sketches relating Instructing Cadets, Dartmouth can be found within the Imperial War Museum, this is the only other oil on the subject known to exist.