He turned to Lord Peter with a sudden realization. “I’m sorry,” he said. “I didn’t mean to imply—”
”That’s all right, Your Highness,” Lord Peter said. “It’s a common reaction. Their spies are dirty, filthy scum, not fit to wipe your boots on, while our spies are noble gentlemen doing dangerous work for the love of King and Country. Would that it were so, Your Highness, but I’m afraid that sometimes the desired image is at fault—in both directions.”
Source: Ten Little Wizards (1988), Chapter 4 (p. 33)
Quotes about spy
page 2

Quoted in Venezuelan Opposition Spreads Lies About U.S. Journalists, Inciting Violence, Death Threats, by Ben Norton, AlterNet https://www.alternet.org/news-amp-politics/venezuela-abby-martin-mike-prysner-lies-death-threats (3 June 2017)

"Hard is the Road of Life"
1950's
"Born American, But in the Wrong Place" (2006)

“Heir sall Wantones ga spy them and cum agane to the king. (in Scottish)”
Ane Satyre of the Thrie Estaitis, Stage direction, line 326