The public service broadcaster committed a "major breach" of broadcasting rules by omitting to mention that the narrator of a documentary about Gaza was the child of a Hamas administrator, according to regulatory body Ofcom.
An probe by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The head of the BBC had already issued an apology, noting there had been "a significant failing in relation to factual correctness".
Ofcom has ordered the corporation to broadcast a prime-time declaration about its conclusions.
"Since this amounts to a major infringement of our code, we are instructing the BBC to transmit a statement of our conclusions against it on BBC2 at nine o'clock in the evening, with a schedule to be confirmed," it said.
'Risk to Damage Trust'
The authority's statement declared: "Our investigation determined that the programme's lack of disclosure that the presenter's male guardian held a post in the Hamas-administered administration was materially misleading.
"It meant that the audience did not have essential details which may have been extremely pertinent to their assessment of the presenter and the content he shared.
"Trust is at the core of the relationship between a media organization and its public, notably for a public service broadcaster such as the public broadcaster.
"This oversight had the risk to undermine the significantly high amounts of confidence that viewers would have placed in a factual film from the broadcaster about the conflict in Gaza."
The film was withdrawn from the BBC's streaming service in February after the boy's personal associations emerged, and in July an broadcaster's internal assessment determined it violated the corporation's content policies on accuracy.
A BBC spokesperson commented: "The authority's determination is in agreement with the findings of the internal assessment, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on accuracy, which corresponds to clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with Ofcom's decision in its entirety. We will follow the penalty as soon as the timing and wording are confirmed."
