The BBC committed a "significant breach" of media regulations by failing to disclose that the presenter of a programme about Gaza was the child of a Hamas administrator, according to UK media regulator Ofcom.
An probe by Ofcom into the documentary titled Gaza: How to Survive a Warzone has found that the film was "materially misleading".
The BBC's director general had earlier expressed regret, stating there had been "a serious error in relation to accuracy".
Ofcom has ordered the broadcaster to air a prime-time declaration about its conclusions.
"Since this amounts to a serious breach of our regulations, we are instructing the BBC to air a announcement of our determinations against it on BBC Two at 21:00, with a timing to be confirmed," it said.
'Potential to Damage Confidence'
The authority's announcement declared: "Our investigation concluded that the film's failure to disclose that the presenter's male guardian held a role in the Hamas-controlled authority was substantially inaccurate.
"Consequently that the public did not have essential details which may have been extremely pertinent to their evaluation of the voice and the content he provided.
"Trust is at the heart of the relationship between a broadcaster and its public, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the potential to erode the significantly high amounts of confidence that viewers would have put in a factual film from the broadcaster about the conflict in Gaza."
The documentary was removed from the online platform in last February after the presenter's family links came to light, and in July an corporation's own inquiry determined it violated the broadcaster's journalistic standards on truthfulness.
A corporation official commented: "The authority's determination is in agreement with the conclusions of Peter Johnston's review, that there was a serious error in the film in relation to the broadcaster's journalistic policies on factual correctness, which corresponds to regulation 2.2 of the regulator's media standards.
"We have apologised for this and we agree with the regulator's ruling in its entirety. We will adhere to the sanction as soon as the timing and language are confirmed."
