The British broadcaster was found to have committed a "serious breach" of industry standards by omitting to mention that the voice of a film about the Gaza conflict was the child of a Hamas official, according to UK media regulator Ofcom.
An investigation by the broadcasting watchdog into the documentary titled Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The head of the BBC had already issued an apology, saying there had been "a major oversight in relation to factual correctness".
Ofcom has instructed the broadcaster to air a peak-time declaration about its findings.
"Since this amounts to a serious breach of our rules, we are instructing the broadcaster to transmit a message of our findings against it on BBC2 at 9pm, with a date to be finalised," it said.
'Risk to Damage Trust'
The watchdog's statement declared: "Our investigation determined that the programme's lack of disclosure that the voice's parent served in a role in the Hamas-administered administration was substantially inaccurate.
"It meant that the audience did not have essential details which may have been very significant to their assessment of the narrator and the information he shared.
"Credibility is at the heart of the bond between a media organization and its viewers, especially for a public service broadcaster such as the public broadcaster.
"This oversight had the risk to undermine the significantly high degrees of credibility that audiences would have placed in a documentary produced by the BBC about the conflict in Gaza."
The documentary was removed from iPlayer in last February after the presenter's family links came to light, and in this past July an internal BBC review found it breached the broadcaster's journalistic standards on accuracy.
A representative for the broadcaster stated: "The Ofcom ruling is in accordance 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 accuracy, which corresponds to Rule 2.2 of the regulator's media standards.
"We have apologised for this and we agree with Ofcom's decision in its entirety. We will adhere to the directive as soon as the schedule and language are determined."
