Following Bond's reckless pursuit and killing of a bombmaker in Madagascar, M and Villiers attended a parlimentary imposition; afterwards, the former remarked that she missed the days of the Cold War, when a spy with Bond's lack of tact "would have the good sense to defect."
Some time later, after Bond had begun investigating leads in the Bahamas related to a corrupt official, Alex Dimitrios, Villiers woke M with a phone call alerting her that Bond was accessing the MI6 network with her credentials; this being noticed was a deliberate move by Bond, alerting his superior officer to the network he was chasing, headed by terrorist financier Le Chiffre.
As a result of Bond's intervention into the plans of Dimitrios and Le Chiffre, he uncovers a plot to profit from a shorting of airline stocks. The agent calls Villiers to alert M to this development; running a quick search, Villiers confirms that a prototype aircraft is being unveiled at Miami International, where Bond tracked the bomber. Bond managed to thwart the attacker at the last minute, though the bomber and Dimitrios, as well as the latter's wife, Solange, ended up dead as a result.
When M and Villiers arrived in the Bahamas to brief Bond on the true extent of things, the latter gagged upon seeing Solange's open-eyed corpse, covering his mouth with the back of his hand and walking away from the scene while M spoke to her subordinate.
At some point, Villiers was replaced by Vanessa.
Behind the scenes
Villiers was played by Tobias Menzies in the 2006 film Casino Royale. The characters' name was a reference to James Villiers, who played Bill Tanner in For Your Eyes Only, as well as Amherst Villiers, an automotive expert namedropped in the original Casino Royale novel.