The British broadcaster was found to have committed a "significant breach" of industry standards by not revealing that the voice of a film about the Gaza conflict was the son of a Hamas administrator, as determined by British broadcasting authority Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The head of the BBC had earlier expressed regret, stating there had been "a significant failing in relation to factual correctness".
The regulator has directed the BBC to transmit a peak-time declaration about its conclusions.
"Since this amounts to a serious breach of our regulations, we are ordering the corporation to air a message of our conclusions against it on the BBC's second channel at 21:00, with a schedule to be finalised," the statement read.
'Potential to Undermine Trust'
The watchdog's announcement said: "The inquiry we conducted determined that the documentary's lack of disclosure that the presenter's father occupied a role in the Hamas-run government was significantly deceptive.
"Consequently that the public did not have critical information which may have been highly relevant to their assessment of the presenter and the information he provided.
"Trust is at the heart of the connection between a broadcaster and its viewers, particularly for a public service broadcaster such as the BBC.
"This failing had the possibility to damage the exceptionally strong levels of credibility that the public would have put in a BBC factual programme about the Gaza conflict."
The film was withdrawn from iPlayer in February after the presenter's familial connections were revealed, and in July an internal BBC review found it infringed the broadcaster's editorial guidelines on truthfulness.
A corporation official stated: "The regulator's decision is in agreement with the findings of the corporation's inquiry, that there was a significant failing in the film in relation to the broadcaster's journalistic policies on truthfulness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with the authority's determination in complete. We will follow the penalty as soon as the schedule and wording are confirmed."
