The public service broadcaster committed a "serious breach" of industry standards by failing to disclose that the voice of a programme about Gaza was the child of a Hamas representative, according to British broadcasting authority Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had earlier expressed regret, noting there had been "a serious error in relation to accuracy".
The regulator has instructed the BBC to transmit a prime-time announcement about its conclusions.
"As this represents a serious breach of our code, we are instructing the BBC to air a statement of our findings against it on BBC2 at 21:00, with a date to be determined," the statement read.
'Potential to Erode Trust'
The authority's statement said: "Our investigation found that the programme's failure to disclose that the narrator's male guardian served in a role in the Hamas-administered administration was substantially inaccurate.
"Consequently that the audience did not have essential details which may have been very significant to their assessment of the presenter and the details he provided.
"Credibility is at the core of the relationship between a television network and its public, notably for a public service broadcaster such as the public broadcaster.
"This failing had the potential to damage the exceptionally strong levels of trust that audiences would have invested in a documentary produced by the BBC about the Israel-Gaza war."
The programme was pulled from the BBC's streaming service in the month of February after the boy's family links were revealed, and in July an corporation's own inquiry found it violated the broadcaster's journalistic standards on factual correctness.
A corporation official said: "The regulator's decision is in accordance with the conclusions of the corporation's inquiry, that there was a major oversight in the documentary in relation to the BBC's Editorial Guidelines on truthfulness, which aligns with Rule 2.2 of the regulator's media standards.
"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 language are confirmed."
