His US-based lawyer, Andrew Brettler, told a pre-trial hearing last month that he believed it released the Duke and others from “any and all potential liability.”

The agreement was last week released to the Duke’s legal team on the orders of a judge.

The reference to royalty is likely to be seized upon by his legal team as they argue that it nullifies Ms Giuffre’s claim.

No other member of the Royal family has been implicated in the Epstein scandal or is thought to have come into contact with Ms Giuffre, allowing them to insist it could only apply to Prince Andrew.

The reference appears to accord with Ms Giuffre’s original complaint against Epstein, filed under the pseudonym Jane Doe in Florida, which stated: “In addition to being continually exploited to satisfy the defendant’s every sexual whim, Plaintiff was also required to be sexually exploited by defendant’s adult male peers, including royalty, politicians, academicians, businessmen and/or other professional and personal acquaintances.”

The ensuing settlement was used by Alan Dershowitz, Epstein’s former lawyer, to get an abuse claim Ms Giuffre made against him struck out.

Chance of case being dismissed

He urged the judge in his case, Loretta Preska, to unseal the document, warning he was “not compelled not to sit back silently” knowing its contents.

“The issue before the court is a matter of professional ethics and the interests of justice,” he said.

Mr Dershowitz told the Telegraph: “I cannot imagine how the case against the Prince will not be dismissed based on the dismissal of the case against me.”

However, it is understood that while the royal reference is considered helpful to the Duke’s case, and gives his team grounds to argue that it should be thrown out, it is not quite as clear cut as they might have hoped.

David Boies, Ms Giuffre’s lawyer, has described it as “irrelevant” to the case.