The BBC was found to have committed a "significant breach" of industry standards by omitting to mention that the presenter of a film about the Gaza conflict was the son of a Hamas administrator, as determined by regulatory body Ofcom.
An investigation by Ofcom into the documentary titled Gaza: How to Survive a Warzone has determined that the film was "substantially inaccurate".
The head of the BBC had earlier expressed regret, stating there had been "a significant failing in relation to accuracy".
The authority has directed the broadcaster to broadcast a prime-time announcement about its findings.
"Given this constitutes a significant violation of our rules, we are directing the BBC to air a announcement of our findings against it on BBC2 at 9pm, with a schedule to be finalised," it said.
'Potential to Damage Trust'
The regulator's announcement declared: "Our probe found that the programme's omission to reveal that the narrator's parent held a role in the Hamas-controlled authority was materially misleading.
"Consequently that the audience did not have critical information which may have been highly relevant to their judgment of the voice and the information he presented.
"Confidence is at the center of the relationship between a broadcaster and its audience, notably for a national broadcasting corporation such as the public broadcaster.
"This oversight had the risk to erode the very considerable levels of confidence that audiences would have put in a factual film from the broadcaster about the Gaza conflict."
The documentary was pulled from the BBC's streaming service in the month of February after the presenter's family links emerged, and in July an corporation's own inquiry found it infringed the broadcaster's journalistic standards on accuracy.
A corporation official said: "The authority's determination is in agreement with the findings of the corporation's inquiry, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on truthfulness, which aligns with regulation 2.2 of the regulator's media standards.
"We have apologised for this and we agree with Ofcom's decision in complete. We will comply with the penalty as soon as the timing and wording are finalised."
