I'll reveal more GCHQ secrets, says Snowden ally: Journalist who helped leak documents threatens fresh revelations about Government listening post

• Glenn Greenwald helped Edward Snowden to leak CIA documents
• He has threatened to reveal names of people targeted by US government
• Said British spy agencies were more vicious and unrestrained than US
  

By Ian Drury for the Daily Mail

Published: 20:51 EDT, 18 May 2014 | Updated: 15:10 EDT, 19 May 2014

Glenn Greenwald threatened to reveal reveal the names of citizens targeted by the US government, saying he was saving 'the best for last'

The journalist who helped Edward Snowden leak millions of British and American intelligence secrets has threatened to publish fresh revelations about GCHQ.

Glenn Greenwald said the UK’s eavesdropping post was ‘unrestrained and vicious’ compared to their counterparts at the US National Security Agency (NSA).

He also said he would reveal the names of citizens targeted by the US government, saying he wanted to ‘save the best for last’.

Snowden, 30, became one of the world’s most wanted men last June when he broke cover as the civilian CIA worker who stole classified documents from the US National Security Agency.

He leaked details of attempts by state spy agencies - including Britain’s GCHQ - to view citizens’ private information.

It showed that intelligence chiefs harvested internet histories, emails, text messages, calls and passwords.

The defence contractor, who was a computer specialist at an intelligence centre in Hawaii, copied up to 2million files in one of the biggest leaks in US history - on a par with WikiLeaks whistleblower Bradley Manning - then handed the secrets to the Guardian.

Promising more revelations about GCHQ, Mr Greenwald said: ‘The British are more unrestrained and vicious in their surveillance mindset than America.

‘When you go to the park in New York you see these big built-up muscular guys and they have these tiny shih-tzu dogs.

‘It will seem a mismatch but the shih-tzu is super-vicious and yapping.

‘That’s how I see the relationship between GCHQ and the NSA.’

His pledge to publish more damaging material in The Intercept, the online magazine for which he now works, will unnerve security chiefs on both sides of the Atlantic who are still reeling from their surveillance activities being exposed.

Snowden, 30, became one of the world¿s most wanted men last June when he broke cover as the civilian CIA worker who stole classified documents from the US National Security Agency

Mr Greenwald said: ‘One of the big questions when it comes to domestic spying is: “Who have been the NSA’s specific targets?”

‘Are they political critics and dissidents and activists? Are they genuinely people we’d regard as terrorists?

‘What are the metrics and calculations that go into choosing those targets and what is done with the surveillance that is conducted?

‘Those are the kinds of questions that I want to still answer.

‘As with a fireworks show, you want to save your best for last.

‘The last one is where the sky is all covered in spectacular multicoloured hues.’

Mr Greenwald spoke out as speculation mounted that Snowden could have been a spy working - unwittingly or need - for Russia or China.

Intelligence chiefs believe he is now a ‘puppet’ passing details of military capabilities, operations and tactics to unfriendly nations.

Snowden claims he acted after becoming convinced the US government’s actions were a ‘threat to democracy’.

He fled to Hong Kong, then Moscow, where he was granted asylum and now lives in a secret location.

Mr Greenwald said: ‘It’s obviously so irrational but it resonates with so many of these tribal themes - how the Russians function and how the Chinese are menacing - and it’s just a standard demonisation tactic.’