The BBC was found to have committed a "significant breach" of industry standards by failing to disclose that the voice of a film about Gaza was the child of a Hamas administrator, as determined by UK media regulator Ofcom.
An investigation by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The BBC's director general had previously apologised, saying there had been "a serious error in relation to truthfulness".
The regulator has ordered the BBC to air a prime-time statement about its findings.
"Given this constitutes a serious breach of our rules, we are instructing the corporation to transmit a announcement of our conclusions against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be confirmed," it said.
'Possibility to Damage Confidence'
The watchdog's statement stated: "Our investigation determined that the film's failure to disclose that the presenter's parent held a post in the Hamas-run government was substantially inaccurate.
"Consequently that the public did not have essential details which may have been very significant to their judgment of the voice and the content he provided.
"Confidence is at the heart of the connection between a media organization and its audience, particularly for a public service broadcaster such as the public broadcaster.
"This error had the potential to damage the very considerable levels of confidence that audiences would have invested in a BBC factual programme about the Gaza conflict."
The film was removed from iPlayer in February after the boy's familial connections came to light, and in July an broadcaster's internal assessment concluded it violated the broadcaster's content policies on factual correctness.
A BBC spokesperson said: "The Ofcom ruling is in agreement with the conclusions of Peter Johnston's review, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the authority's determination in full. We will adhere to the sanction as soon as the schedule and wording are confirmed."
