In the novel The Secret Adversary, Edward Whittington is an operative of Kramenin's gang, an organisation which British authorities thought to be ultimately controlled by a mysterious "Mr Brown". When Tuppence first met him, he used the company Esthonia Glassware Co. as a front.
Whittington offered Tuppence a job to pose as his ward and seek admission to a pensionat run by one Madame Colombier in Paris. When he asked Tuppence for her name, Tuppence gave one which she heard used recently, Jane Finn, which greatly alarmed him. He became suspicious that Tuppence might be trying to blackmail him and hurriedly gave her fifty pounds as a payoff.
Whittington was described as being a "big man, clean-shaven, with a heavy jowl". His eyes were "small and cunning".
Whittington was seen by Tommy and Tuppence, leaving South Audley Mansions, where Mrs Vandemeyer lived. He later travelled to Bournemouth, and was followed there by Julius Hersheimmer. In Bournemouth, Whittington goes to Dr Hall's nursing home, and speaks with Nurse Edith.
Whittington is later seen at Astley Priors in Kent, where he is dressed as a butler.