A journalist has accused the Iranian channel Press TV of colluding in his wrongful imprisonment after he was detained for filming protests during last year’s presidential elections in Iran.

Freelance documentary maker Maziar Bahari has taken his case against Press TV – which launched in Britain three years ago and broadcasts to nearly ten million UK subscribers - to Ofcom, the broadcasting standards watchdog.

Mr Bahari, who now lives in Britain, accuses the channel of breaching Ofcom rules on privacy and fairness for recording his forced confession inside a Tehran prison.

Press TV, an English language channel funded by the Tehran government, describes itself as providing a 'voice for the voiceless.'

With glossy presenters, and colourful sets, it is the model of an international 24 hour news channel. Broadcasting live from London, and Tehran, it features an array of local and international talent, including Yvonne Ridley, George Galloway and Lauren Booth.

When it launched in Britain, it promised to be independent, delivering different views and unbiased reports.

But in an interview with Channel 4 News, to be broadcast tonight, Mr Bahari explains that Press TV betrayed those promises, by sending a journalist to cover his forced confession in Tehran's notorious Evin prison.

'I was somewhat surprised because I thought Press TV would at least pretend to have some credibility and wouldn't come and interview a prisoner in an interrogation room when I was under duress.'

Mr Bahari says he was tortured and then forced to make his confession on television, under threat of execution. He describes how he sat inside a room in the prison, before three cameras, and responded to questions suggested by a government interrogator, who stood behind a red curtain. He says he kept his blindfold on his knee, in full view, so it should have been clear that he was under duress.

Press TV then broadcast the confession, as though it was a legitimate interview, and Mr Bahari a willing guest; the presenter even suggested Mr Bahari might have participated in the protests.

The Iranian-Canadian journalist captured defining moments of the demonstrations - later broadcast on Channel 4 News, with whom he has worked for many years.

But he paid a high price - spending 118 days in detention, and was only released after a vigorous international campaign. Last month, he was convicted in absentia on five charges, including conspiring against the state, and insulting the Supreme Leader. He was sentenced to 13 and-a-half years in prison, and 74 lashes.

A former current affairs presenter at Press TV, Shahab Mossavat, described the actions of the channel as appalling and tragic.

He left the network last year after his show was axed, but says there is increasing political pressure on the channel from Tehran, despite its aspirational beginnings.

'Iran wanted to engage, and set its own agenda for engagement, so in those ways, I think Press TV was apposite,” he told Channel 4 News.

“As time went on, that changed, and having played the game, the people at Press TV, and much higher than Press TV, realised they weren't winning. Then the tone changed and became much more shrill and much less palatable.”

Press TV says it determines its own editorial policy and maintains complete independence from the government - suggesting Shahab Mossavat resigned after his employers couldn't meet his demands for a pay rise.

The broadcaster says it won't comment on Mr Bahari's allegations while Ofcom makes its deliberations.

The case is being closely watched by human rights activists. Index on Censorship campaigner, Jo Glanville says any respectable journalist should refuse to work for the channel. “The way they behaved by going into the prison in that way and essentially colluding with the torture and illegal detention of a journalist that should finish their reputation once and for all in this country.”

For the full report, see Channel 4 News tonight at 7pm