A Metropolitan Police sergeant has been sacked after a woman member of staff alleged he engaged in sexual activity in a north London police building.
A disciplinary hearing managed by the Independent Police Complaints Commission heard the alleged incident took place in Islington last August.
The case was handed to the Crown Prosecution Service but no charges were brought.
The IPCC said the officer had been dismissed after a misconduct hearing.
The accused officer sent away several Police Community Support Officers home early so that the building was deserted, the hearing by Met's Directorate of Professional Standards was told.
Rachel Cerfontyne, of the IPCC, said: "The Met misconduct panel found that this woman was vulnerable and that the police sergeant engineered a situation whereby he was alone with her in a police building.
"Behaviour of this kind falls far below the standards expected from a police officers and it will not be tolerated."
Jennette Arnold, who represents Islington on the Metropolitan Police Authority, said the decision "sends a signal throughout the service to say this is unacceptable".