US whistleblower Edward Snowden has delivered a Christmas message on British television.

Mr Snowden warned about the global threat to privacy when he delivered the Channel 4 Alternative Christmas Message this afternoon.

Mr Snowden, who was behind a leak of documents revealing mass surveillance programmes, said in the broadcast: "Great Britain's George Orwell warned us of the danger of this kind of information.

"The types of collection in the book - microphones and video cameras, TVs that watch us - are nothing compared to what we have available today.

"We have sensors in our pockets that track us everywhere we go. Think about what this means for the privacy of the average person.

"A child born today will grow up with no conception of privacy at all. They'll never know what it means to have a private moment to themselves, an unrecorded, unanalysed thought.

"And that's a problem because privacy matters, privacy is what allows us to determine who we are and who we want to be."

He added: "The conversation occurring today will determine the amount of trust we can place both in the technology that surrounds us and the government that regulates it.

"Together we can 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."

Mr Snowden, a computer analyst, became a wanted man more than seven months ago when his leaks brought to light secret National Security Agency documents which revealed widespread US surveillance on phone and internet communications.

It led to not only embarrassment but also friction with other countries when the extent of the surveillance emerged.

Mr Snowden's passport was revoked and a warrant was issued for his arrest - for passing on classified information and theft of government property - when his leaks came to light.

Channel 4 said it was his first recorded TV film since Mr Snowden arrived in Moscow, where he has been given asylum.

Channels 4's head of news and current affairs Dorothy Byrne said: "Edward Snowden's decision to reveal the extent of surveillance programmes was one of the most significant news events of the year.

"The information which he has placed in the public domain raises serious questions for democratic society. This is an opportunity for our viewers to hear from him directly and judge for themselves what he has to say."

Mr Snowden follows figures such as Ali G, Sharon Osbourne and Baroness Lawrence in giving the festive address.

It is the station's answer to the British queen's message to the nation.