A full-length portrait wearing a captain's undress uniform (over three years, 1774-87) of frock coat and breeches. Facing left, Montagu stands in front of a tree to his left with the sea beyond, to his right. The ship is stern view is probably the firgate 'Pearl', 32 guns, of which he was in command when he captured the Spanish frigate 'Santa Monica', 28 guns, in 1779 and in the following year the large French privateer, 'Espèrance', 32 guns. As a rear-admiral, he commanded the secondary squadron watching Rochefort in the campaign of the First of June, 1794, and was later commander-in-chief at Portsmouth, dying as Admiral of the Red.

This fine portrait was bequeathed to the Museum in 1958 from the estate of James Drogo Montagu, a descendant of the sitter, but the artist -certainly British- has not yet been firmly identified though both Lemuel Abbott and Thomas Beach have been suggested. Its rather compressed format is because the canvas has been cut down top and bottom.