The BBC committed a "significant breach" of broadcasting rules by failing to disclose that the narrator of a documentary about Gaza was the offspring of a Hamas administrator, according to regulatory body Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The chief executive of the broadcaster had already issued an apology, noting there had been "a significant failing in relation to factual correctness".
Ofcom has instructed the broadcaster to air a peak-time announcement about its findings.
"Since this amounts to a major infringement of our rules, we are instructing the corporation to broadcast a announcement of our findings against it on the BBC's second channel at nine o'clock in the evening, with a date to be determined," it said.
'Risk to Undermine Confidence'
The authority's statement stated: "Our investigation found that the film's failure to disclose that the voice's parent held a post in the Hamas-administered government was substantially inaccurate.
"Consequently that the viewers did not have vital facts which may have been very significant to their judgment of the voice and the content he shared.
"Confidence is at the core of the relationship between a television network and its audience, notably for a state-funded media outlet such as the public broadcaster.
"This error had the potential to erode the significantly high levels of credibility that the public would have placed in a factual film from the broadcaster about the Israel-Gaza war."
The film was pulled from iPlayer in last February after the narrator's familial connections were revealed, and in this past July an internal BBC review determined it infringed the broadcaster's editorial guidelines on truthfulness.
A BBC spokesperson said: "The regulator's decision is in line with the findings of the corporation's inquiry, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on truthfulness, which aligns with Rule 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with the regulator's ruling in full. We will adhere to the penalty as soon as the schedule and wording are finalised."
