The BBC engaged in a "major breach" of media regulations by omitting to mention that the voice of a programme about the Gaza situation was the offspring of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An probe by the media regulator into the documentary titled Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The head of the BBC had earlier expressed regret, noting there had been "a significant failing in relation to truthfulness".
The regulator has instructed the broadcaster to air a peak-time declaration about its findings.
"Since this amounts to a major infringement of our code, we are directing the broadcaster to transmit a announcement of our determinations against it on BBC Two at 9pm, with a date to be determined," the regulator stated.
'Possibility to Damage Trust'
The regulator's statement said: "Our probe determined that the programme's lack of disclosure that the narrator's male guardian held a post in the Hamas-controlled authority was significantly deceptive.
"It meant that the audience did not have vital facts which may have been very significant to their assessment of the presenter and the content he shared.
"Confidence is at the core of the connection between a broadcaster and its audience, notably for a public service broadcaster such as the BBC.
"This oversight had the risk to damage the very considerable amounts of trust that the public would have placed in a documentary produced by the BBC about the conflict in Gaza."
The documentary was removed from iPlayer in February after the presenter's family links were revealed, and in this past July an internal BBC review determined it infringed the broadcaster's content policies on accuracy.
A BBC spokesperson stated: "The authority's determination is in line with the findings of Peter Johnston's review, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which reflects clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the regulator's ruling in complete. We will adhere to the directive as soon as the date and wording are determined."
