This depiction of the Battle of Cape St Vincent is compositionally very close to Nicholas Pocock's 1808 version (BHC0487) that he completed for reproduction in Clarke and McArthur's two-volume publication, ‘Life of Nelson’. However, differences in style and content are sufficient to suggest, firstly, that this painting is not by Pocock, and secondly, that it is not directly based on Pocock's version. Instead, both pictures appear to have a common source in the engraving produced by James Fittler after a drawing by Lieutenant Jahleel Brenton of the Royal Navy, which was published on 4 June 1798, the year following the battle. The engraving, though expanded to the left to include a more panoramic view of the fleets, has the same composition showing the broadside of the ‘Captain’ with the two Spanish ships, ‘San Nicolas’ and ‘San Josef’, just beyond to the right.

Whereas Pocock's version shows the moment when the Spanish vessels were being boarded by the crew of the ‘Captain’ under Nelson's command, here the British flags placed above the Spanish ensigns indicate that the ‘San Nicolas’ and ‘San Josef’ have now been taken. Differences in the disposition of the ships in the background also indicate that a slightly later moment in the battle is being shown here. However, the closeness of this composition to both Fittler's engraving and Pocock's painting suggests that this picture was executed, like Pocock's, in the early years of the 19th century.