Ms Giuffre, who claimed she was sexually assaulted by Prince Andrew three times after being trafficked by Epstein, died by suicide at the age of 41 in Western Australia in April.
Prince Andrew has always strongly denied any wrongdoing involving Ms Giuffre.
The email, published by the Mail on Sunday and the Sun, read: “You have always been a steadfast, generous and supreme friend to me and my family.”
It appeared to have been sent a few weeks after she said in an interview that Epstein was “rightly jailed” in 2008, and that she had broken off contact with him.
Ms Roberts told Newsnight that the duchess should “for sure” lose her courtesy title.
“If you are not one to stand up if you actively know or see that these things are happening, you shouldn’t hold those titles,” Roberts said.
A courtesy royal title is one held by those who are associated with a peer or member of the royal family but do not hold a substantive title.
The duchess has retained her title despite her divorce from Prince Andrew, in the same way that Diana, Princess of Wales kept her title after her separation from King Charles, then the Prince of Wales.
Prince Andrew lost his royal patronages and military titles over the court case brought against him by Ms Giuffre, but he has retained the title of Duke of York.
On Monday, seven charities – including the Teenage Cancer Trust and British Heart Foundation – announced that the duchess had been removed as either patron or ambassador following the publication of the email.
A spokesperson for the duchess said that she would not be commenting on the charities’ decision to remove her.
Ferguson said she had “humbly apologised” and knew Epstein would feel “hellaciously let down by me”.
‘ The preceding article may include information circulated by third parties ’
‘ Some details of this article were extracted from the following source www.bbc.co.uk ’
