The BBC committed a "serious breach" of industry standards by failing to disclose that the voice of a programme about the Gaza conflict was the son of a Hamas official, as determined by British broadcasting authority Ofcom.
An probe by the media regulator into the documentary titled Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The head of the BBC had previously apologised, stating there had been "a serious error in relation to truthfulness".
Ofcom has instructed the broadcaster to broadcast a peak-time statement about its conclusions.
"Since this amounts to a serious breach of our rules, we are ordering the broadcaster to transmit a announcement of our findings against it on the BBC's second channel at 21:00, with a schedule to be finalised," the statement read.
'Possibility to Erode Credibility'
The authority's report said: "The inquiry we conducted found that the documentary's lack of disclosure that the narrator's father occupied a position in the Hamas-controlled administration was materially misleading.
"This implied that the public did not have essential details which may have been extremely pertinent to their assessment of the voice and the details he presented.
"Confidence is at the heart of the bond between a media organization and its audience, especially for a public service broadcaster such as the public broadcaster.
"This oversight had the potential to undermine the exceptionally strong degrees of confidence that viewers would have invested in a factual film from the broadcaster about the conflict in Gaza."
The documentary was withdrawn from the online platform in February after the presenter's family links came to light, and in the month of July an broadcaster's internal assessment concluded it violated the corporation's editorial guidelines on truthfulness.
A corporation official said: "The Ofcom ruling is in accordance with the results of Peter Johnston's review, that there was a significant failing in the programme in relation to the broadcaster's journalistic policies on truthfulness, which corresponds to clause 2.2 of the regulator's media standards.
"We have apologised for this and we accept Ofcom's decision in complete. We will comply with the directive as soon as the timing and language are determined."
