Jake Davis was found guilty of conspiracy and was barred for two years from even setting up an email account.
As "Topiary", he was the witty spokesman for the group of hacktivists once dubbed the "most-wanted cyber-criminals on the planet".
He was the chief promoter for Anonymous and offshoot LulzSec as they went on a high-profile hacking spree in 2011, targeting the likes of News International (replacing the Sun homepage with a fake story claiming Rupert Murdoch had died), Sony, the CIA, the UK's Serious Organised Crime Agency, the Arizona police force and even a website affiliated with the FBI.
It all ended for Jake Davis two years ago when he was arrested in his home in the Shetland Islands on suspicion of more than 80 charges of conspiracy.
He eventually pleaded guilty to two counts ("with intent to impair the operation of a computer") and was banned from doing anything on the internet for two years.
He was also electronically tagged and locked up at Feltham Young Offenders Institution for 37 days.
While the American LulzSec-member-turned-FBI-informant "Sabu" remains in US custody, where he faces a maximum of 124 years in jail, Davis, now 20 years old, is eating a smoked salmon bagel in a cafe in central London.
The Scot, who set up LulzSec's Twitter account (it quickly acquired more than 300,000 followers), now lives with his partner and freelances for three film and digital companies.
He is still on probation and is not allowed to leave the country, erase his internet history, or speak to anyone currently or formerly associated with Anonymous or its offshoots.
He is giving a talk on his experience at Wired 2013 to an audience who have paid more than 1500 ($2860) each to attend the two-day conference this weekend.
He is also planning on publishing a "nerd's perspective" on his time behind bars.
Davis shrugs off the threat of being extradited to the United States (he was also indicted for his crimes in America), and said would-be hackers should be helped to find a "different outlet for their creativity".
He is adamant that if you give most hackers a "reward mechanism" or a job, they'll "immediately drop what they're doing". And he warns against portraying hackers as an "elite cool" who "go against the system in an edgy way" because it will encourage more people to do it.
Davis says the life of a hacker is not glamorous. "I would never have done it if there was something else outside my front door to get involved with," he told the Independent.
He left school at 13 "on a whim", spending all his time alone on a "very slow Shetland internet connection".
Without "any sort of outward stimuli", he turned to the online world to fill his days.
"That led to me becoming a very stereotypical basement-dwelling nerd who played online games and sat on Skype calls for 18 hours a day without really leaving the house," he said.
Davis moved out of his mum's house and into his own when he was 17. His father took his own life several years ago - Davis is vague about when.
It was shortly after visiting a chatroom where a "bunch of internet people were rising up against PayPal" that he became involved with Anonymous. He says he just wanted to "go there and mess with them and generally make jokes", but after leaving the tab open on his computer screen he got drawn in.
He helped promote LulzSec, intending to showcase "activism via digital satire". After choosing the top-hatted avatar for their Twitter account and trying to parody the "pointless" Twitter campaigns that "galvanise fan bases", he found his voice. But he quickly lost control of the hackers.
Sabu, the group's reported ringleader, was arrested by the FBI in2011 and persuaded to become aninformant.
"The people who wanted to attack the CIA, FBI and Soca were the people the FBI was using to try to entrap others," said Davis, who always said he never hacked an account himself.
"It was a stupid way to make a point," he adds. "It was a bunch of silly kids not really knowing what they were doing."
Today, Davis believes it's important for young people to be taught that "actions have consequences".
"There is no way the internet teaches empathy," he says. "When a person is described as a victim of computer hacking, many of these hackers wouldn't understand [how] they could be a victim, because they're not a real person, just lines on the internet and an avatar. That's kind of the trap I fell into - [I was] devoid of any emotion."
After his arrest and subsequent internet ban, Davis moved to the Midlands where he lived with his mother, whom he describes as "very supportive".
Banned even from setting up an email account, he found it impossible to attend college and hard to find work, but he says it was nice to "have that sense of attention span back".
At Feltham, he was greeted as a bit of a hero, getting high-fives from inmates as he arrived. One prisoner even defended him when another started insulting him.
"He put down his pool cue and went right up in his face, and said: "Don't f*** with the hacker or I will break your neck," Davis says.
He remembers Feltham as an "awful place" that was "dank, disgusting and dusty".
Davis says the guards at Feltham had no idea how to deal with him.
"I got sacked from my job of cleaning because they thought it was too dangerous for me to mop near a computer. I don't know what they thought I would do," he says.
Before his arrest, Davis deleted his tweets [@atopiary], leaving only one: "You cannot arrest an idea."
After being inside, Davis is adamant that putting hackers behind bars isn't the solution.
"Hackers aren't a danger to anyone on the street. If a hacker is caught, instead of enforcing preposterous laws which send them to prison for 126 years, the authorities should try to find some avenue in which they can be beneficial to society."
Davis is now back on Twitter, but does not want to return to the world of internet forums. It is still unclear whether he regrets getting involved with the hackers .
"If I had closed down the computer and left, I'd probably still be in the Shetlands, most likely conforming to their ways of farming and drinking and knitting, or dressing up as a Viking," he said.
"I regret that it hurt so many people, and that it was so criminal. But it's the same answer a lot of people would give if you ask, 'do you regret anything?' You can't."
Independent