A Scottish newspaper has printed a description of an alleged incident involving the Prince of Wales and named another person said to be involved.
A spokesman for the prince said the claims were "totally false"
Prince Charles has flown back from a royal tour of Oman to a series of headlines in the Sunday newspapers.
The precise nature of the alleged incident had not been reported in the UK because of a High Court injunction obtained by former royal servant, Michael Fawcett, against the Mail on Sunday.
The Sunday Herald can print details because the injunction preventing publication of the story only applies in England and Wales.
The story has not been published on the newspaper's website but editions can also be bought in parts of Northern England and London.
On Saturday the prince was described by royal aides as "unruffled" about the media frenzy.
In London, a spokesman for the prince said there was concern that full details of the allegations may appear.
"Yes, we are concerned about allegations being published which are totally false - that's why we have made our position very clear," he said.
The Daily Telegraph's legal affairs editor Joshua Rozenburg told BBC Radio Scotland's Sunday Live programme that the allegation would soon appear in other newspapers.
"This story is pretty close to being out, even though some of us are being a little bit cautious," he said.
The paper printed details of the allegation
"I think everybody in the media is looking to see what everyone else is doing, just prepared to do what everybody else is doing because there is safety in numbers.
"Within a day or so, perhaps tomorrow's papers, then pretty well the full allegations that have been denied by the palace will be published."
The Mail on Sunday was blocked last Saturday from publishing the allegations but did not publish details this week, instead carrying an interview with former royal servant, George Smith, who made the allegations.
Clarence House said in a statement on Thursday the claims were "ludicrous" and "untrue".