A woman has told a court of her "embarrassment" when one of England's most senior judges exposed himself to her on a rush-hour train.
Sir Stephen Richards has presided over many high-profile cases
Lord Justice Richards faces two counts of exposure on trains in south-west London on 16 and 24 October 2006.
On the first occasion, she thought the "presentable" and "very kind" man was accidentally exposed, the court heard.
Sir Stephen Richards, 56, a father of three from Wimbledon, south London, denies the charges.
The victim identified the Court of Appeal judge and even took his pictures on a mobile phone, before picking him out at a video identity parade, City of Westminster Magistrates' Court heard.
Recalling the first incident the woman said he had "boxed" her into a corner against the glass panels in the first carriage on the trip from Raynes Park, south-west London to Waterloo.
"Because I was embarrassed and nothing like this had happened to me before, I assumed this was an accident... so I carried on reading my paper," she said.
"Sometimes the gentleman would adjust himself slightly, sometimes his genitals would be exposed and sometimes not as much."
She said the incident lasted about 15 minutes.
A week later she spotted the judge on the train again, "My gut instinct then led me to believe that this was not an accident."
When she realised he was exposing himself, she took out her mobile phone to unnerve him, the court heard. She then reported the incident following her boyfriend's advice.
The court heard she took four photos of the judge on her mobile phone camera on two other occasions when she spotted him on the train, but this time he recognised her and moved away.
In January she boarded the train with a police officer and identified him.
During his police interview Sir Stephen insisted it was a case of mistaken identity.
Peter Wright QC, prosecuting, said Sir Stephen exposed himself "for what must be unfathomable reasons".
During the trial David Fisher QC, defending, accepted it was possible the victim had seen Sir Stephen on two occasions but stressed he was not the same man.
Recalling his police interview, arresting officer Pc Adrian Watts told the court Sir Stephen had said: "It would be a very extraordinary thing to do, to have walked on to a crowded commuter rail service with one's penis hanging out.
"If that had happened I would have expected somebody to point it out, I would.
"I simply have to say that what she is alleging, if she is alleging it, is untrue."
Sir Stephen has overseen several high-profile hearings, including the case brought by the family of Jean Charles de Menezes, seeking action against police officers over the killing of the Brazilian at Stockwell Tube station in south London.
The trial is expected to last two days.