In 1803 Harris was drafted into the 66th Regiment of Foot somewhat against his will, and forcibly marched to Winchester, where he underwent training in preparation for deployment against the French as the Peace of Amiens was drawing to a close.

It was whilst stationed there that he was randomly selected as part of a firing squad to execute a deserter, an action which he reports "for many years afterwards remained deeply impressed on my mind".

Many of his companions were killed at this action and the ensuing Battle of Vimeiro, but Harris remained unhurt, continuing the march to Salamanca before becoming trapped in northern Spain with the rest of Sir John Moore's army.

The sights and horrors of the march remained with him for decades to come, and he was lucky to escape, claiming to be the very last man collected from the beaches at Vigo, and embarking for England in a severely weakened state.

The expedition totally failed, as it was unable to take any of the island's major towns and bivouacked in squalid conditions during the summer, resulting in a plague of malaria and typhoid which killed over 4,000 soldiers and permanently disabled 12,000 from a force of 40,000.

Harris was amongst those disabled, spending months in plague wards from which he was never expected to recover, and on at least one occasion only surviving through the extra medical care he received thanks to his financial reserves.

Although this character was not intended to represent the real Benjamin Harris, there are a number of small details and lines of dialogue that were included as references to the historical person - he is shown repairing his comrades' shoes, and his commanding officer suggests that, in order to get rich, he write a book about his soldiering days, "full of battles and death".