A British teenager charged with hacking offences and believed to be a leading member of the Anonymous and LulzSec online activist groups was released on bail in a London court on Monday on condition he did not use the Internet.

Jake Davis, 18, who goes by the online nickname of Topiary, was charged with computer attacks on Sony, UK crime and health authorities and Rupert Murdoch's UK newspaper arm News International.

Anonymous and LulzSec members have been arrested in the United States, Spain, Turkey, Britain and the Netherlands in recent weeks in a crackdown on attacks on targets seen by the activists as hostile to Internet freedom of speech.

The arrest of Topiary in Scotland's remote Shetland Islands may be the most significant to date in the global effort to end the cyber-crime spree by the groups.

Davis, a slight, dark-haired youth who spoke only to confirm his name and date of birth and suppressed a smile when the prosecutor struggled to pronounce LulzSec, was released on bail under strict conditions.

He will be allowed no Internet access and will live under a curfew with his mother and brother, who have just moved to Lincolnshire in eastern England and have not yet arranged a broadband connection.

His lawyer, Gideon Cammerman, said that while Davis had helped to publicize the work of the cyber activists, there was no evidence to show he had the expertise to have taken part in any of the hacks.

The picture that emerges is not one of a skilled and practised hacker but of someone who sympathizes, he said.

LulzSec and its parent group Anonymous, loose online collectives of activists, have attracted widespread global media coverage for their stunts. LulzSec has more than 350,000 followers on Twitter.

The prosecution said on Monday that police had seized a Dell laptop from Davis's home in Shetland with a 100 gigabyte drive running 16 different virtual computers.

Files found on the computer included details of an attack on Sony, email addresses and passwords of hundreds of thousands of members of the public and hundreds of other folders that had not yet been examined, the prosecutor said.

When police arrived to arrest Davis, his computer screen was displaying a dialogue box for a single-use email address with a lifespan of 10 minutes, the prosecution said. Forty other applications were also running.

The Shetland Islands, off the northeast coast of Scotland, have some of Britain's poorest Internet connections, with no superfast broadband availability and an average speed of 5.5 megabits per second, according to telecoms regulator Ofcom.

Davis, who has no previous criminal convictions, is due to appear for his first trial hearing on August 30 in Southwark Crown Court, London.

(Reporting by Georgina Prodhan; Editing by Mark Heinrich)