Two men tried to blackmail a member of the Royal Family over claims he had performed a gay sex act, a court heard today.

Ian Strachan, 30, and Sean McGuigan, 40, are alleged to have made "an unwarranted demand for £50,000 from a male with menaces" between January and September 2007.

The junior member of the Royal Family in question, who cannot be named for legal reasons but will be known as A during the trial, is not due to be a witness.

The audio tape the pair used is also said to contain references to "impropriety" in the Royal's business dealings.

Mark Ellison QC, for the prosecution, told the court that in early 2007, the pair made the recordings of a man “for whom they have professed a strong dislike”, and had been previously employed by the member of the extended Royal Family.

The recordings are believed to be have been made when the man was drunk or “under the influence of other substances”, the court heard.

The court heard how the material reveals him "making allegations of impropriety as to how his employer conducted aspects of his business,” and giving opinions “on a wide range of other members of the Royal Family - which included a number of scandalous and disparaging remarks”.

“And there were three audio files of the man apparently asserting that the member of the Royal Family who employed him had performed an act of oral sex on him," Mr Ellison added.

Strachan of Fulham and McGuigan of Battersea both deny the charge.

Members of the public will be banned from court during parts of the trial involving the playing of a DVD recording, trial judge Mr Justice Cooke ruled.

The trial is expected to last three weeks.