A single mother turned whistleblower is threatening to expose the murky goings on inside a top-secret Russian agency where staff pose as housewives and soldiers to pump out pro-Putin propaganda.

Russia's 'troll factory', a shadowy 'internet research' hub - akin to something out of George Orwell's 1984 - is based in nondescript concrete office on the outskirts of St Petersberg.

Until recently it operated undetected under the radar for years, to such an extent that very few people knew it even existed.

Whistleblower: mother of two Lyudmila Savchuk is revealing what goes on in Vladimir Putin's highly-secretive propaganda factory where internet trolls pump out pro-Kremlin stories

The Kremlin has always denied the existence of The Agency for Internet Studies. 'We know nothing about this agency and have never had any contacts with it,' said Putins spokesman Dmitry Peskov

This glass and concrete building at 55 Savushkina Street on the edge of St Petersburg is the hub of Vladimir Putin's propaganda machine, claim whistleblowers who have worked inside its high security doors

But now Lyudmila Savchuk, a civic activist, who worked undercover there for two months, is threatening to open up its Pandora's box of secrets.

In an extraordinary employment tribunal which has gripped Russia, Ms Savchuk has gone to court to try and get The Agency for Internet Studies, its official name, closed down.

Threatening to reveal what really goes on there, Ms Savchuk told how she created three different fictional characters to post comments online praising Putin.

At the same time, she said was ordered to criticise Ukraine, the US and the European Union.

She described how armies of online foot soldiers pose as ordinary Russians to write hundreds of biased comments on social media.

If Joseph Goebbels was alive today, he'd be proud of this operation. It is sinister, powerful and skewing democracy

They comment on topics such as sanctions, the Ukraine conflict, the seizure of Crimea, the shooting down of flight MH17 and assassinations of Putin enemies - like Boris Nemtsov -

The case has led one Russian PR executive to call it sinister, powerful and skewing democracy' - adding: 'If Joseph Goebbels was alive today, he'd be proud of this operation.'

The Kremlin officially denies all knowledge of the 'troll factory', even disputing its existence.

'We know nothing about this agency and have never had any contacts with it,' Putin's spokesman Dmitry Peskov said.

'We couldn't have contacted with it, since we don't know what it is and what it does. And even if it exists indeed.'

Ms Savchuk, 34, did 12-hour stints posting diatribes she describes as 'very dangerous' due to their extremism.

Many of the trolls are students, but they take on other identities for their postings. One posed as a fortune teller, she said.

'From the beginning I was an agent, not a troll,' she told Der Spiegel.

'I only played the role of an employee. It was interesting. But every day I was in shock, realising what large-scale work is done and how many trolls exist, even if we take only this factory.'

There is an atmosphere of 'utmost secrecy' inside the plant and she 'never saw the bosses' in overall charge, she said.

She added she had seen staff posting comments onto Facebook, Twitter, YouTube, and Livejournal.com as well as the Russian networks like VK.com and Odnoklassniki.

Mother of two Lyudmila Savchuk went undercover and worked at Vthe Kremlin's troll factory for two months. She is now exposing its work which she sees as fanning hatred in Russia

Whistleblower, Marat Burkhart, 40, who worked there said internet trolls were set quotas of having to write 135 pro-Kremlin comments per 12-hour shift

And she warned that there are more offices in Russia.

'A few colleagues reported about work trips to a Moscow office. There is also information about a further, highly secretive building in St. Petersburg.'

In the building offices are separated into different departments.

There is the 'Administration of Bloggers and Commentators,' 'Rapid Reaction Department,' and an office for 'Journalists', among others.

Job adverts for the agency - where there is no talking, staff are fined for being just a minute late and personal relationships are frowned upon - first emerged in 2013.

Potential recruits were told their responsibilities of 'the placement of comments on target Internet sites, writing on-topic posts, blogs, social networks'.

Ms Savchuk, a mother of two, revealed that one group of trolls 'masquerades as journalists'. She said it has fake news portals that pretend to be Ukrainian news sites, with names like 'Kharkiv News' or the 'Federal News Agency.'

Bosses are said to have ordered trolls to refer to Ukrainians opposed to Putin as Nazis.

In another shocking claim, a second whistleblower Marat Burkhart said he was asked to refer to Barack Obama as a 'monkey'.

"The worst was when we had to humiliate Obama, comparing him with a monkey," he said. "I wrote it, I had to.'

Ms Savchuk, who earned up to 50,000 roubles (£585) a month, said she was ordered 'to write about how terrible things are in the European Union'.

Another time she was supposed to praise Russian Defence Minister Sergey Shoigu.

'You sit there and write things like: 'Yesterday I went for a walk and the idea came to me about how bad the situation is in Europe'.'

She said she felt 'sickened' when Nemtsov was gunned down close to the Kremlin and she was ordered to smear him on the web, claiming that he was probably killed by friends who turned on him.

Entrepreneur Yevgeniy Prigoshin - said to be a personal friend of Putin's - is rumoured to be behind the scheme. He has declined to comment.

Prigoshin runs a major catering business which has won major state contracts, including from the army.

The agency is seeking to avoid public scrutiny by offering to compensate Ms Savchuk, who is seeking the symbolic sum of 10,000 roubles (£116).

Lawyer Yekaterina Nazarova, defending, this week told Petrogradsky district court judge the agency is willing to settle with Ms Savchuk.

Yet the case has exposed what goes on there, her supporters claim.

Ms Savchuk made clandestine videos and copied documents before being sacked when she leaked her revelations to a local newspaper.

She revealed how staff were told to turn on proxy servers to obscure their IP addresses and avoid detection.

Then they began posting 'patriotic' comments, monitored by their chiefs, using key words chosen each day by their bosses to fit the news agenda.

'I want to get it closed down,' she said.

'These people are using propaganda to destroy objectivity and make people doubt the motives of any civil protest.

'Worst of all, they're doing it by pretending to be us, the citizens of Russia.'

Since her name was disclosed, she has faced a backlash from online trolls.

Recruits to the four-storey plant are sought by headhunters.

Ms Savchuk said some staff realise they are part of 'a pro-Kremlin troll factory' - but turn a blind eye for the money.

The second whistleblower, Mr Burkhart, 40, recalled of his time: 'First they make you write something neutral - Vegetarianism: the Pros and Cons.

'After that, the assignments start to get more to the point - for example, what do I think about humanitarian convoys in Donetsk?'

He claimed he had to mask his true beliefs to get a job.

'I'm pro-Western. That's natural for me and for them, of course, it's not.

'I didn't write anything about my views. Otherwise, they wouldn't have hired me; they would have thrown me out immediately.'

Mr Burkhart said bosses constantly ran ideological checks on all comments - and that trolls were paid according to their output.

'It's a real factory. There are production quotas,' he said. 'The quota is 135 comments per 12-hour shift.'

Staff at Putin's propaganda hub pose as housewives and soldiers to post pro-Kremlin comments on news websites, and social media like Facebook and Twitter

Whistleblower Lyudmila Savchuk said: 'You sit there and write things like: 'Yesterday I went for a walk and the idea came to me about how bad the situation is in Europe'.'

Marat Burkhart, 40, (pictured) said he felt uncomfortable criticising Putin's enemies online. He claimed he had to mask his true beliefs to get a job.'I'm pro-Western. That's natural for me and for them, of course, it's not.'

A typical task was to post comments claiming NATO troops were embedded with Ukrainian forces onto 35 forums.

He claimed had an unsuccessful interview with the troll factory's English department - because during the interview he told them he was apolitical.