A Philadelphia schoolteacher, she was married to a man assigned to a British Army unit as an artillery repairman. Her husband joined the British troops evacuating Philadelphia and marching to New York City in 1778. Claiming to be a patriot, she carried a unique token (description still unknown) that would identify her as a British spy to an American officer who was spying for the British. Both British Major Duncan Drummond and later Major John Andre would get reports from her as "Mrs. Barnes." She had further credibility with a pass from then American General Benedict Arnold. By the time she reached the American lines (she was selling merchandise), she walked into the headquarters of Gen. George Washington. "I had the Opportunity of going through their whole Army Remarking at the same time the strength & Situation of each Brigade, & the Number of Cannon with their Situation and Weight of Ball each Cannon was Charged with," she later wrote lines and stayed at safe houses as they made their way back to British-held territory. Major Drummond planned to use her against Washington's Culper Spy Ring but he and Ann were unable to make contact with a British spy on Long Island. In October, 1778, she was sent to assist a fellow female British spy to British lines and in this she was successful. But from October, 1778 through August, 1779, she undertook no new spy missions but in August, 1779, Major Andre (Major Drummond had been sent back to England due to a disagreement with General Clinton) asked her to assist him in regard to another female British spy which she did successfully. She was also involved in the General Arnold treason affair as well. From late August, 1779 to May, 1780, there is no record of Ann performing any missions. An old friend, British Colonel Nesbit Balfour called on Ann for assistance in operating a spy ring out of Charleston, South Carolina. This she did in regard to General Cornwallis' army but both missions were aborted. On March 6, 1781, Ann and her husband sailed for England. Living the life of a spy and in contact with some of the most famous people of the American Revolution, caused Ann's marriage to wither with her husband Joseph Bates leaving her. She immediately contacted Major Duncan Drummond to assist her in securing a pension from the British government for her services during the American Revolution. Major Drummond's personal papers, official government documents, and her memory secured her a long overdue pension.