The female police officer who was arrested over alleged media leaks about the "plebgate" affair was present at Downing Street during the time of the incident in September, the Metropolitan Police said.
More top news
Two pilots have been arrested on suspicion of being under the influence of alcohol as they prepared to fly from Scotland to the New York.
Two teenagers have been arrested on suspicion of drugs offences following the death of a 17-year-old youth who collapsed at Leeds Festival.
Theresa May will gather Cabinet ministers together on Wednesday to discuss her plans for Brexit.