The broadcasting standards watchdog has fined the Tehran-backed channel, Press TV, £100,000 for multiple breaches of its code.
In October it emerged that Ofcom was considering imposing sanctions in Press TV following the broadcast of an interview with jailed Newsweek journalist Maziar Bahari in July 2009. A subsequent investigation found that the programme breached its standards on fairness and privacy.
Mr Bahari later said that the interview, in which he spoke about covering the Iran election protests, was a forced, scripted confession, under threat of execution.
In the ruling, Ofcom said the hefty fine had been imposed because of "the seriousness of the breaches".
"The committee considered that the case represented serious and deliberate breaches of the code because of the vulnerable circumstances of the complainant Mr Bahari, the lack of steps to obtain his informed consent and the effect the broadcast had on him," it said.
Ofcom's ruling also said the penalty should also encourage Press TV "not to repeat the material found in breach on any future occasion".
Ofcom also said Press TV had to broadcast a statement of Ofcom's findings on the channel. Press TV is funded by the Iranian government. It broadcasts in English to nearly 10 million homes in the UK, with presenters past and present including George Galloway, Lauren Booth and Yvonne Ridley.