The Metropolitan Police launched an investigation on Friday “after officers were made aware of a video allegedly filmed inside HMP Wandsworth”.
It said a woman was arrested on suspicion of misconduct in public office the same day and taken into police custody.
Linda De Sousa Abreu, 30, has now been charged and will appear in custody at Uxbridge Magistrates’ Court on Monday, the Met Police said.
Wandsworth is a category B men’s prison in southwest London.
Last month, a “deeply concerning inspection” at the prison found severe overcrowding, vermin, drugs, violence and rising self-harm.
A watchdog said the jail should be put into emergency measures after the inspection raised concerns over ongoing failings in security following the alleged escape of Daniel Khalife in September last year.
The chief inspector of prisons Charlie Taylor wrote to the justice secretary Alex Chalk to issue an urgent notification for improvement.
Khalife, 22, is due to go on trial at the Old Bailey in October and has pleaded not guilty to the charges against him.
