The BBC engaged in a "major breach" of industry standards by failing to disclose that the voice of a film about the Gaza conflict was the child of a Hamas official, as determined by regulatory body Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a serious error in relation to factual correctness".
Ofcom has ordered the broadcaster to transmit a prime-time declaration about its findings.
"As this represents a major infringement of our rules, we are directing the BBC to air a statement of our conclusions against it on the BBC's second channel at 9pm, with a timing to be confirmed," the statement read.
'Potential to Erode Credibility'
The watchdog's statement said: "Our investigation found that the film's lack of disclosure that the voice's parent served in a post in the Hamas-administered authority was significantly deceptive.
"This implied that the audience did not have vital facts which may have been very significant to their evaluation of the presenter and the content he provided.
"Trust is at the heart of the connection between a broadcaster and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the risk to erode the exceptionally strong amounts of credibility that the public would have invested in a documentary produced by the BBC about the Israel-Gaza war."
The film was removed from iPlayer in last February after the presenter's family links emerged, and in this past July an corporation's own inquiry determined it violated the organization's journalistic standards on factual correctness.
A BBC spokesperson commented: "The regulator's decision is in line with the conclusions of the internal assessment, that there was a significant failing in the documentary in relation to the corporation's content standards on factual correctness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the authority's determination in complete. We will follow the directive as soon as the schedule and language are finalised."
