The BBC committed a "major breach" of media regulations by omitting to mention that the narrator of a film about the Gaza situation was the son of a Hamas representative, according to regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The chief executive of the broadcaster had previously apologised, saying there had been "a serious error in relation to factual correctness".
The regulator has ordered the broadcaster to broadcast a peak-time announcement about its findings.
"As this represents a significant violation of our regulations, we are ordering the broadcaster to transmit a statement of our findings against it on BBC Two at 9pm, with a date to be confirmed," the statement read.
'Risk to Erode Confidence'
The watchdog's statement declared: "Our investigation found that the documentary's lack of disclosure that the presenter's father held a position in the Hamas-run authority was significantly deceptive.
"Consequently that the public did not have essential details which may have been very significant to their evaluation of the voice and the details he shared.
"Trust is at the center of the bond between a media organization and its public, notably for a national broadcasting corporation such as the BBC.
"This error had the potential to damage the significantly high amounts of confidence that the public would have put in a documentary produced by the BBC about the Gaza conflict."
The film was pulled from the BBC's streaming service in last February after the presenter's family links came to light, and in the month of July an internal BBC review concluded it violated the corporation's journalistic standards on accuracy.
A BBC spokesperson said: "The regulator's decision is in line with the conclusions of the corporation's inquiry, that there was a significant failing in the film in relation to the broadcaster's journalistic policies on factual correctness, which corresponds to Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we comply with the authority's determination in complete. We will adhere to the directive as soon as the timing and language are determined."
