LONDON (Reuters) - A London court hearing, reported to be Apple's appeal against a British government order to create a "back door" to its encrypted cloud storage systems, was held in secret on Friday, with media not allowed to attend despite a formal request.

In February, The Washington Post reported that Britain had issued a "technical capability notice" to the tech firm to enable access to encrypted messages and photos, even for users outside the country. 

The iPhone maker in response removed its most advanced security encryption for cloud data, called Advanced Data Protection, for new users in Britain.

Details of the case have been shrouded in secrecy, and neither Apple nor the British government has publicly confirmed the technical capability notice.

The BBC reported a hearing on Friday simply listed as "an application in private" at the Investigatory Powers Tribunal, a court that considers allegations of unlawful intrusion by public bodies, was Apple's appeal against this order.

There was no confirmation of what parties were involved, although James Eadie, who represents the government in its most serious legal cases, attended. He declined to comment. Apple did not immediately respond to a request for comment.

A lawyer representing 10 media organisations, including Reuters and the BBC, submitted an application to the tribunal for the case to be held in public.

The court confirmed receipt of his email but he was not invited to appear before the judges to make any further submissions on Friday, and no reporters were allowed in the courtroom. The hearing concluded after about six hours.

'UNACCEPTABLE AND DISPROPORTIONATE'

Two civil rights groups, Privacy International and Liberty, have also challenged the secrecy of the case and the issuing of the technical capability notice itself. Caroline Wilson Palow, Legal Director at Privacy International, said it was "unacceptable and disproportionate". 

"People the world over rely on end-to-end encryption to protect themselves from harassment and oppression," she said. "No country should have the power to undermine that protection for everyone."

Governments and tech giants have long been locked in a battle over strong encryption to protect consumers' communications, which the authorities believe can be an obstacle to investigations into crimes from terrorism to child sex offences. 

But Britain's demands are seen as particularly sweeping.

"We told them you can't do this," U.S. President Donald Trump told the Spectator magazine in an interview last month about the British demand. "That's something ... that you hear about in China."

U.S. officials are also investigating whether Britain violated a bilateral pact by pressuring Apple as the move could breach the CLOUD Act, which bars Britain from issuing demands for the data of U.S. citizens and vice versa.

Britain's Home Office (interior ministry) has declined to comment on the case, and Security Minister Dan Jarvis told parliament last month the government operated a policy of neither confirming nor denying the existence of TCNs.

"What I can say is that the suggestion that privacy and security are at odds is not correct; we can and must have both," he said.