Ms Pomerantz said the heiress, who has spent the past 15 months in a federal prison in Brooklyn, used her “cover of respectability” to lull Epstein’s victims, at the start of what has already been dubbed the “trial of the century”.

“Make no mistake, she knew what Epstein was going to do. He did not abuse (the victims) alone, she was in the room for the abuse,” said Ms Pomerantz, who warned the jury that some of what was alleged would be “hard to hear”.

Ms Pomerantz described Ms Maxwell as “essential” to Epstein’s abuse of the girls.

“Sometimes, she was even in the room for the massages herself, and sometimes she touched the girls’ bodies,” Ms Pomerantz said.

“And even when she was not in the room, make no mistake: she knew exactly what Epstein was going to do with those children when she sent them to him inside the massage rooms.”

Ms Maxwell “was involved in every detail of Epstein’s life,” the prosecutor said. “The defendant was the lady of the house.”

The prosecution will call on victims of Epstein, relatives of those victims, Epstein’s staff and law enforcement officials in a bid to put Ms Maxwell at the centre of his dark network.

Standing outside the court in Lower Manhattan, Sarah Ransome, an alleged victim of Ms Maxwell, was overcome with emotion.

“I have so many emotions. I never thought this day would come. Ever,” she said as she choked back tears.

“I’ve waited 26 years for this,” tweeted Maria Farmer, one of Ms Maxwell’s and former partner Epstein’s alleged victims, whose sister is one of the four accusers due to testify.

Isabel Maxwell, Ghislaine’s older sister, was the only member of the family present in court. Scott Borgerson, Ms Maxwell’s husband and an American entrepreneur who offered up millions of dollars in collateral for her failed appeals for bail, was notably absent.

A dozen jurors, plus six alternates, were whittled down from a pool of 60 on Monday morning to sit for what is expected to be a six-week hearing, masked and socially distanced in a pandemic-era courtroom.

One of those selected worked for a financial institution, as Epstein had done, but said he could be impartial. Most of those picked had either read or heard about the financier’s sex trafficking ring, which will prove a challenge for the defence to overcome.