A walk-in agent is an individual who voluntarily offers to conduct espionage. Specifically, a "walk-in" is an agent or a mole of a government who literally walks into an embassy or intelligence agency without prior contact or recruitment.
Famous quotes containing the words walk-in and/or agent:
“With four walk-in closets to walk in,
Three bushes, two shrubs, and one tree,
The suburbs are good for the children,
But no place for grown-ups to be.”
—Judith Viorst (b. 1935)
“I wish not to be given a title or an appointed position. I can and will do more good if I were made a Federal Agent at Large, and I will help best by doing it my way through my communications with people of all ages. First and Foremost I am an entertainer but all I need is the Federal Credentials.”
—Elvis Presley (1935–1977)