Agnes Reeves Taylor, 51, is suspected of ordering and carrying out torture between 1989 and 1991, during a civil war in the West African state.

She is to be tried at the Old Bailey, the Central Criminal Court, on 30 June.

Up to 250,000 people are believed to have been killed in Liberia's civil war, which ended in 2003.

Ms Reeves Taylor, of Dagenham in east London, was arrested on Thursday.

She has not commented on the charges. One accuses her of agreeing with "a course of conduct" that "would necessarily amount to or involve the commission of the offence of torture".

The other charges allege that she along with "others unknown at Gbarnga, Liberia, intentionally inflicted severe pain or suffering on an individual in the performance or purported performance of her official duties".

Gbarnga was the headquarters of Charles Taylor's National Patriotic Front during the civil war.

Taylor served as president from 1997 to 2003, when he was forced into exile.