LONDON - National Security Agency whistleblower Edward Snowden invoked George Orwell and warned of the dangers of unchecked government surveillance Wednesday in a televised Christmas message to the British people that reflected his growing willingness to take a public role in the debate he ignited.

Speaking directly into the camera from Moscow, where he took refuge after leaking vast troves of information on NSA spying, Snowden said government surveillance methods far surpassed those described in Orwell's novel 1984.

"The types of collection in the book - microphones and video cameras, TVs that watch us - are nothing compared to what we have available today," he said. "We have sensors in our pockets that track us everywhere we go. Think about what this means for the privacy of the average person."

The brief video marked Snowden's first television appearance since he fled possible prosecution in the United States and arrived in Moscow in June. It came days after the Washington Post published an extensive account of Snowden's comments during more than 14 hours of interviews.

In the Post interview, Snowden said he had succeeded in spawning the debate he sought by bringing the extent of surveillance by the U.S. and British governments to light.

"The mission's already accomplished," he said. "I already won. As soon as the journalists were able to work, everything that I had been trying to do was validated. Because, remember, I didn't want to change society. I wanted to give society a chance to determine if it should change itself."

Snowden echoed those sentiments Wednesday, saying he sees an opportunity to "find a better balance, end mass surveillance and remind the government that if it really wants to know how we feel, asking is always cheaper than spying."

Snowden, 30, a former NSA contractor, has been condemned by authorities in the United States for jeopardizing security on both sides of the Atlantic by divulging vital information about programs used to spy on hostile governments and would-be terrorists.

In June, federal prosecutors charged Snowden with theft, unauthorized communication of national defense information and "willful communication of classified communications intelligence information to an unauthorized person."

Snowden, who is living under temporary asylum in Russia, had until this week kept a low profile there, referring to himself in the Post interview as an "indoor cat."

Snowden's video was recorded for Britain's Channel 4, which for two decades has been broadcasting the Alternative Christmas Message - an at-times irreverent counterpoint to the queen's traditional holiday greeting.

Previous alternative messages have been delivered by then-Iranian President Mahmoud Ahmadinejad and the cast of The Simpsons.