- "I assume I'm expendable, sir."
"You're a soldier aren't you? Of course you're expendable!"
- — Sharpe & Nairn
Nairn is a major-general who serves as deputy for Wellington when the latter is away from camp.
He is described as a middle aged Scotsman whose huge grey eyebrows were attempting to reach up to meet a shock of grey hair. He was irreverent, throwing letters from the Chaplain General into the fire, and his staff liked him enormously as did Sharpe.
In Sharpe's Revenge, at Toulouse he is given command of a brigade, and takes the detached Richard Sharpe as his Chief of Staff. With the war winding down, he guesses it will be his only chance to lead men into battle.
Riding beside Sharpe, a French artillery attack killed Sharpe's horse, and moments later, a second volley of canister staggers Nairn. Alarmed, Sharpe turned back to him. Nairn sent him onward, claiming it was only a leg wound. Wounded but exultant, he would not let Sharpe stay with him, and ordered Sharpe to fire a volley and keep the momentum of the attack going.
With a victory in hand, a bagpipe sounded on the field. Nairn's body, carried on a litter made of enemy jackets, was recovered. Shrapnel had pierced his lung as well as his leg, and he had died at the battle's end. He was buried in the center of the redoubt his men had captured. Sharpe wept. (Sharpe's Revenge)
Nairn is Wellington's main intelligence officer in the second season of the television series. He often uses Sharpe and his men in the course of his operations and is on close enough terms with them to consult with Hagman Hagman when Sharpe is believed dead.
Nairn has a good relationship with Sharpe, although they have a number of disagreements, notably in Sharpe's Company when Sharpe sees Nairn as putting Teresa in danger by leaving her as a spy in Badajoz. It is while on a mission for Nairn, that Teresa is killed by Hakeswill.
He delights in poking fun at the officious Sir Augustus Farthingdale, seemingly without Farthingdale realizing.