A school bus has been driven past Buckingham Palace carrying a billboard urging the public to ask Prince Andrew to call the FBI.
The stunt was reportedly arranged by a lawyer representing Jeffrey Epstein's accusers.
The banner on the side of the bus, which includes a picture of the Duke of York, states:“If you see this man please ask him to call the FBI to answer their questions."
The poster on the side of the bus also featured the website address for attorney Gloria Allred - who is representing several of Jeffrey Epstein’s accusers.
During a press conference in New York last year she said Prince Andrew has an obligation to meet with investigators to disclose what he knew about Epstein.
Onlookers said the bus was pulled over by police in Park Street, close to Hyde Park.
An onlooker who spotted the “weird bus” said officers spoke to the driver for around ten minutes before the bus was allowed to drive off.
Images of the vehicle have been spotted all over London in a high visibility campaign.
Virginia Giuffre, who claims she was trafficked by Epstein, also alleges the duke had sex with her on three separate occasions, including when she was 17, still a minor under US law.
Andrew, who strenuously denies the allegations, has faced calls to talk to the FBI and US prosecutors still investigating Epstein, who committed suicide in jail while facing sex trafficking charges.
The duke was due to be promoted to Admiral on his 60th birthday, in line with a longstanding policy that sees senior royals treated as serving military members.
But Buckingham Palace has already said the duke has asked to defer the promotion until he is able to fully resume royal duties.
Earlier this month an open letter written by four of Epstein's alleged victims implores the Duke of York to act now for the sake of his daughters.
It says: “Please help the US authorities with anything you may have observed in your time spent with Jeffrey Epstein.
“Do it for the victims who have lived a life of suffering... and humiliation.
“You can make things better for us and for future generations with your co-operation. Do it for your daughters and their children.
“You have a chance to be on the right side of history. The world is watching.”
The prince has vehemently denied her accusations, saying in a BBC interview in November that the alleged sexual incidents “never happened”.
Days after the broadcast Andrew, 59, quit public life “for the foreseeable future” because of his “former association” with Epstein.
The duke also said he is “willing to help any appropriate law enforcement agency with their investigations”.
But FBI federal prosecutor Geoffrey Berman last week said Andrew “has provided zero co-operation”.
This claim reportedly left the duke “angry and bewildered”. Sources close to him reportedly said he had not received any requests for help from the FBI.
Ms Giuffre, now 36, said: “Tick-tock, Andy – time to talk. Do the right thing.”