The public service broadcaster committed a "significant breach" of broadcasting rules by omitting to mention that the narrator of a programme about the Gaza situation was the son of a Hamas representative, as determined by British broadcasting authority Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The BBC's director general had previously apologised, stating there had been "a significant failing in relation to truthfulness".
Ofcom has directed the BBC to broadcast a evening announcement about its decisions.
"Since this amounts to a serious breach of our rules, we are ordering the BBC to air a message of our findings against it on BBC Two at nine o'clock in the evening, with a date to be finalised," the regulator stated.
'Possibility to Erode Credibility'
The authority's announcement said: "Our probe concluded that the programme's lack of disclosure that the voice's parent occupied a role in the Hamas-run administration was materially misleading.
"It meant that the viewers did not have essential details which may have been very significant to their assessment of the voice and the content he shared.
"Trust is at the center of the bond between a media organization and its viewers, especially for a public service broadcaster such as the BBC.
"This error had the potential to damage the exceptionally strong levels of confidence that viewers would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The programme was removed from iPlayer in February after the narrator's familial connections came to light, and in this past July an internal BBC review determined it breached the corporation's content policies on factual correctness.
A BBC spokesperson said: "The regulator's decision is in agreement with the results of the corporation's inquiry, that there was a major oversight in the documentary in relation to the BBC's Editorial Guidelines on factual correctness, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the regulator's ruling in full. We will comply with the directive as soon as the timing and wording are confirmed."
