THE enjoyment of reading revealing biographies is under threat because of legal action by a Canadian folksinger who was determined to keep the secret of what lay under the linoleum in her Irish cottage.

It could affect the “kiss-and-tell” stories in newspapers and on television, and could give stars the power to veto photographs taken in public places.

Publishers and other media interests are now mounting a legal battle against the “backdoor” assault on freedom of expression after Loreena McKennitt — whose albums include The Book of Secrets and The Mask and Mirror, which have had 13m sales worldwide — went to the High Court in London to stop a former friend from publishing a book about her.

Although details of the case are not judged to be important, it was what Mr Justice Eady said in his judgment that has worried legal minds. They fear that the most trivial or anodyne details about a celebrity’s life, even those known to the public, could now be hidden under the guise of protecting privacy.

Times Newspapers (publishers of The Sunday Times), other newspaper groups, the Press Association, the BBC, BSkyB and a number of magazine publishers will go to the appeal court on September 4 to seek permission to intervene in the case. They fear public figures such as politicians and celebrities will use the McKennitt case to try to muzzle information that has already been made public. One media lawyer said: “It would be like trying to make someone a virgin again.”

Famous names who have tried to block unauthorised biographies include J K Rowling, Bono, Mary Archer and Sir John Mortimer.

Eady awarded McKennitt £5,000 (€7,400) damages and an injunction preventing Niema Ash from Hampstead, northwest London, from publishing specific passages in her book Travels With Loreena McKennitt: My Life as a Friend. These included such mundane matters as what lay under her lino, how many bunk beds there were for visitors and what happened when McKennitt was aroused from sleep.

But his judgment went much further. For the first time a British court drew on a 2004 ruling at the European Court of Human Rights that said photographs of Princess Caroline of Monaco shopping in public or in a swimming costume at a beach club breached her right to privacy. He said there was a “significant shift” taking place between the right of freedom of expression and the corresponding interest of the public to receive information and, on the other hand, “the legitimate expectation of citizens to have their private lives protected”.

He said information about an affair between a couple could be protected even if one of them decided to reveal it to the public; incorrect information could breach somebody’s right to privacy; and the fact that something was already in the public domain did not always mean it could be republished.

Ash has lodged an appeal and media organisations are seeking to join the action when it is heard later this year.

Media lawyers say the case has wider ramifications than the long-running case brought against a tabloid newspaper by Naomi Campbell, the supermodel. She won £3,500 damages from the Daily Mirror after it revealed her fight against drug addiction. The Court of Appeal overturned the award but the House of Lords allowed her appeal against that judgment, saying the newspaper had gone too far in detailing her medical treatment.

Under the Eady judgment, celebrities could sue for breach of privacy over the slightest affront to their feelings. They will not have to prove something is untrue, only that it has invaded their privacy.

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Sacha Baron Cohen forced to tone down Brüno