The BBC engaged in a "major breach" of industry standards by failing to disclose that the presenter of a documentary about the Gaza situation was the son of a Hamas administrator, according to UK media regulator Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The BBC's director general had earlier expressed regret, noting there had been "a major oversight in relation to truthfulness".
The regulator has instructed the BBC to air a evening announcement about its decisions.
"Given this constitutes a serious breach of our rules, we are directing the BBC to air a message of our conclusions against it on the BBC's second channel at 9pm, with a schedule to be determined," it said.
'Potential to Undermine Trust'
The authority's announcement stated: "The inquiry we conducted concluded that the film's omission to reveal that the voice's male guardian occupied a position in the Hamas-run government was materially misleading.
"Consequently that the viewers did not have vital facts which may have been highly relevant to their evaluation of the voice and the information he provided.
"Credibility is at the heart of the relationship between a broadcaster and its public, especially for a state-funded media outlet such as the British Broadcasting Corporation.
"This oversight had the possibility to undermine the exceptionally strong degrees of trust that the public would have put in a factual film from the broadcaster about the Gaza conflict."
The programme was pulled from the online platform in last February after the presenter's personal associations came to light, and in this past July an internal BBC review concluded it violated the corporation's editorial guidelines on accuracy.
A BBC spokesperson said: "The Ofcom ruling is in line with the findings of the corporation's inquiry, that there was a serious error in the programme in relation to the broadcaster's journalistic policies on truthfulness, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we comply with Ofcom's decision in complete. We will comply with the penalty as soon as the timing and wording are determined."
