A judge has refused to let a Muslim woman in a full-length burka enter a plea until she reveals her face.
The 21-year-old from Hackney, who is charged with intimidating a witness, said she could not remove the veil in front of men because of her religion.
Judge Peter Murphy said however, she could not stand trial in the veil, which only reveals her eyes, because her identity could not be confirmed.
The woman is due back at Blackfriars Crown Court on 12 September.
Judge Murphy said the principle of open justice overrode the woman's religious beliefs, warning that a different person could go into the dock pretending to be her if she did not show her face.
He said: "It is necessary for this court to be satisfied that they can recognise the defendant.
"While I obviously respect the right to dress in any way she wishes, certainly while outside the court, the interests of justice are paramount.
"I can't, as a circuit judge, accept a plea from a person whose identity I am unable to ascertain."
The woman's barrister, Claire Burtwistle, told the court the woman was not prepared to lower her veil with men in the room and suggested a female police officer or prison guard could identify the defendant and confirm it to the court.
However, Judge Murphy rejected the proposal and said: "It seems to me to be quite fundamental that the court is sure who it is dealing with.
"In my court room, that's going to come first.
"There is the principle of open justice and it can't be subject to the religion of the defendant whether the principle is observed or not."
Judge Murphy adjourned the case for legal argument over whether the defendant should have to remove her veil.
When the woman returns to court she is expected to enter a not guilty plea.