LONDON — Edward Snowden's decision to blow the whistle on the United States National Security Agency's secret surveillance programs highlights the dangers of “coming in the from the cold” — spy lingo for quitting intelligence work.

Currently in asylum in Russia, the former NSA analyst likely faces a long prison sentence for instigating one of the biggest leaks of top-secret documents in U.S. history if he returns home.

Now, a German anti-surveillance collective is seeking to dispel apprehension among other spies who might be contemplating following in Snowden’s footsteps.

"We want to say, 'Quit your job. You don't have to leak, just step out," said Ariel Fischer, co-founder of Intelexit, a service launched in September by the Berlin-based Peng Collective to encourage conflicted spooks to leave the shadowy world of espionage. "The more people do that, the more it can become a movement."

From tips on quitting, to offering counseling on conflicts of conscience, to resignation letter templates, Intelexit seeks to help intelligence workers leave their business – and avoid Snowden’s fate.

"We help people leave the secret service and build a new life," an Intelexit brochure reads.

Intelexit debuted with a series of stunts outside intelligence agency buildings around the world. In Germany, campaigners targeted the NSA's so-called “Dagger Complex” in Darmstadt, an American Army base where 1,100 agents monitor emails, Internet searches and Skype sessions. Intelexit parked a billboard outside the base that mischievously read: "Listen to your heart, not to private calls."

Meanwhile, in the United Kingdom, campaigners parked a billboard outside the “Doughnut,” the headquarters of the Government Communications Headquarters, or GCHQ, in Cheltenham, that read: "The intelligence community needs a backdoor."

Bu GCHQ was one step ahead of the campaigners. The spies knew they were coming.

"There were apparently internal emails warning workers we were coming so they were watching us and knew about us beforehand," Fischer said. "It was very interesting to see how they use surveillance and counter-strategies on society and on people fighting for democratic principles."

The warning meant most GCHQ workers gave a wide berth to campaigners, who were also distributing leaflets, Fischer said.

"We only managed to talk to a few of them who just said, 'Yes, OK, thank you and goodbye,'" he said. "But you mustn't forget they live a daily repression themselves. They couldn't stand there and openly show an interest in an alternative idea because they would be bullied by their colleagues and mistrusted from then onwards."

Their reticence highlights the prevalence of "self-surveillance" in intelligence, analysts say.

"Secret service workers are watched by their employer to a degree that is unknown in any other industry," said Nils Zurawski, a visiting professor at the University of Darmstadt who specializes surveillance. "Even the most obnoxious employer wouldn't come up with that in their wildest fantasies."

But in October, Intelexit returned to ensure its targets got the message.

Appropriating secret services' own tactics, activists flew drones over the Dagger Complex to drop leaflets on to the high-security base, encouraging workers to reconsider the morality of their work.

"We know that there are employees of the Dagger Complex experiencing great moral conflict because of their tacit involvement in spying," Intelexit spokesperson Sascha Flugel said following the action.

Stunts like the drone flyby help movements like Intelexit succeed, according to Wiebke Johanning of the Bewegungsstiftung, a German foundation that secures funding for political and social campaigns.

"It's a good idea to work with the same instruments as the surveillance services just to influence and get the attention of people that are working in the services," Johanning said. "And Intelexit makes it clear that people working in the services have to ask themselves, 'Is it right what I'm doing here?'"

But others are less convinced.

"It is good to target employees and to create this mirror for them to look into, but security services are hyper inclusive. They are in a world of their own and have a reality of their own. And outside of that, everything is enemy territory," said Zurawski. "Every leaflet is coming from the enemy, which will only make them more hyper inclusive and inward looking."

Zurawski praised Intelexit for raising public awareness about the world of espionage, but he didn’t see many spies changing their mind.

“I am just doubtful that you can convince people in such organizations," he added. "Because of this hyper inclusivity they are in a reality apart, and that makes them resistant to these kinds of efforts."

Even so, months after their launch, Intelexit representatives said they are in contact with employees from international intelligence agencies.

Some are sick and tired of sitting at desks and babysitting surveillance targets when they know taxpayers are paying millions to their agencies. Some have moral qualms with mass intelligence or concerns about the ethics of drone strikes.

"Or it's about chauvinism within surveillance,” said Fischer. “Because of the military environment, there is this culture of guys sticking together.”

Many spies want to leave their jobs because they can’t express doubts about their missions, he continued.

"But in that world, you can't really question what [you're] doing because you might be seen as a traitor," he said. "There is this whole internal conflict people go through before taking the step and saying, 'OK, I want to leave.' The biggest part of pushing people out is the security services themselves."

Next for the initiative is establishing direct links with NSA employees.

"We can call workers directly and talk to them, ask them how their day is and how they're doing, be eye to eye with those who watch us," said Fischer.