Sarah Ferguson made an undercover documentary with ITV in 2008 to expose the “appalling” conditions in state-run orphanages.
Posing as a wealthy Briton known only as Sarah, the Duchess captured images of orphans dressed in rags and tied to beds.
The day after the broadcast, the Turkish authorities accused Ferguson of taking part in a politically motivated smear campaign against the country.
Yesterday, a Turkish court accused her in absentia of “going against the law in acquiring footage and violating privacy” of five children.
Though no trial date has been set, Ferguson faces a maximum term of 22-and-a-half years in prison if convicted.
A spokesman for the Duchess said: “The Duchess of York has fully co-operated with both the Turkish and British authorities at all times on this issue.
“British ministers refused to accede to the further requests for legal assistance from Turkey. From a UK perspective, the Duchess has been told by the Home Office that the case is closed.
“The action today reported by the Turkish authorities is news to all.”
The Duchess has insisted that her mission was humanitarian and not political.
Yesterday, a Home Office source is reported to have said: “As it stands, she will not be extradited. The Turkish authorities have no power to do so.”
The Daily Mail quoted a spokesman for the department as confirming that a judge must refuse an extradition request if there is no equivalent offence in British law.