The British broadcaster was found to have committed a "major breach" of media regulations by omitting to mention that the voice of a programme about Gaza was the child of a Hamas administrator, according to regulatory body Ofcom.
An probe by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The head of the BBC had earlier expressed regret, saying there had been "a significant failing in relation to truthfulness".
The authority has instructed the broadcaster to broadcast a prime-time announcement about its conclusions.
"As this represents a serious breach of our rules, we are directing the BBC to transmit a announcement of our findings against it on BBC Two at 9pm, with a date to be determined," the statement read.
'Potential to Erode Trust'
The watchdog's statement declared: "Our investigation found that the documentary's omission to reveal that the voice's male guardian held a role in the Hamas-controlled authority was substantially inaccurate.
"It meant that the audience did not have vital facts which may have been highly relevant to their evaluation of the presenter and the content he shared.
"Credibility is at the core of the connection between a broadcaster and its viewers, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This oversight had the potential to erode the exceptionally strong levels of credibility that the public would have invested in a documentary produced by the BBC about the conflict in Gaza."
The documentary was withdrawn from iPlayer in February after the presenter's familial connections emerged, and in July an internal BBC review determined it breached the corporation's content policies on truthfulness.
A corporation official commented: "The authority's determination is in line with the conclusions of Peter Johnston's review, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on factual correctness, which aligns with Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we accept the authority's determination in complete. We will comply with the directive as soon as the timing and language are confirmed."
