Buckingham Palace does not usually confirm or deny health reports
A newspaper report that the Duke of Edinburgh has had a diagnosis of prostate cancer has been denied by Buckingham Palace.
The palace said the London Evening Standard report was a "serious breach" of privacy and it would be complaining to the Press Complaints Commission.
The "damaging" story was being reported widely, it added in a statement.
The Evening Standard said the prince, 87, had been diagnosed while being treated for a chest infection in April.
The palace statement read: "Buckingham Palace has always maintained that members of the Royal Family have a right to privacy, particularly in relation to their personal health.
"For this reason, we have always refused to confirm or deny the persistent rumours that circulate about their health, particularly during the quieter news months.
"But on this occasion, because the damaging story is now being reported widely, the Duke of Edinburgh has authorised us to confirm that the claim made by the Evening Standard that he has received a 'diagnosis of prostate cancer' is untrue."
The statement added: "We believe there has been a serious breach of the Duke of Edinburgh's right to privacy... we will be asking the PCC to remind all editors of their obligations."
The front-page story, entitled "Prince Philip Defies Cancer Scare", appeared in early editions of London's Evening Standard.
BBC News royal correspondent Nicholas Witchell says the palace is clearly irritated by the story.
He said the palace regarded it as a sufficiently serious intrusion into the duke's privacy that it was taking the unusual step of referring it to the Press Complaints Commission.
The newspaper clearly believes it has a factual basis for its story, our correspondent added.
The palace said the duke's itinerary, which includes events in Edinburgh next week, would go ahead as planned.
Prince Philip spent three days in the King Edward VII's Hospital west London in April.
The prostate gland, which is about the size of a walnut, produces the liquid that nourishes, protects and carries sperm on ejaculation. It is located below the bladder and in front of the rectum.
Prostate cancer is the most common male cancer in the UK, accounting for almost a quarter of male cancers.
Each year, nearly 32,000 men in the UK are diagnosed and more than 10,000 die from the disease.
There is a greater risk of getting prostate cancer with age - most men who are diagnosed are over 50.