The Queen’s Platinum Jubilee celebrations will be “overshadowed” by the Duke of York’s civil sex trial and lead to questions about the “relevancy” of the royal family, a leading lawyer has said.

Media lawyer Mark Stephens said Andrew would also face detailed questions of a sexual nature when he gives evidence, whether in person or via video link, in the jury trial expected towards the end of the year.

But depending on developments, there was still the prospect the duke may reach an out-of-court settlement with Virginia Giuffre who is suing the Queen’s son for sexual assault. The duke denies the allegations.

Mr Stephens said any trial could have far-reaching consequences for the wider royal family.

He said: “I can’t conceive that the royal family will allow him to run this case and overshadow the Platinum Jubilee.

“It’s going to spark debate about the relevancy and appropriateness of the royal family and we’ve already seen that they moved very fast to strip him of his titles and that debate abated but the more detail that comes out the more there’s going to be a problem for the wider royal family.”

Commenting on lurid details that may emerge from the trial, Mr Stephens said: “For example, questions will be asked of Virginia Giuffre about the prince’s body, any marks, his performance, what positions were adopted – every detail that is conceivable to ask and then that will be put to Andrew.”

He speculated the duke may still pull back from a trial to avoid the legal spectacle which could damage the standing of the monarchy in the Queen’s Platinum Jubilee year.

He said: “The reason we think he’s got to settle is because of the timing. Essentially this case is going to take up the rest of this year and if it takes up the rest of this year, that’s the whole of his mother’s Platinum Jubilee.

“The only thing he could have done to stop this getting worse is to have pulled the case and stopped it in some way so there was no alternative news. This is going to be crippling if he really is dead set on running this to a trial.”

The issue has begun to affect other members of the royal family, with the Duke of Cambridge facing a question about his uncle when he visited London’s Foundling Museum with his wife last week.

A broadcast journalist from Sky asked William “Do you support Andrew?” as the couple left, but he did not respond.