The public service broadcaster committed a "serious breach" of industry standards by failing to disclose that the narrator of a film about the Gaza conflict was the offspring of a Hamas official, according to British broadcasting authority Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had already issued an apology, stating there had been "a significant failing in relation to accuracy".
Ofcom has instructed the corporation to transmit a peak-time declaration about its decisions.
"As this represents a serious breach of our code, we are instructing the BBC to air a statement of our conclusions against it on BBC Two at 9pm, with a timing to be confirmed," the regulator stated.
'Potential to Erode Credibility'
The regulator's statement declared: "The inquiry we conducted found that the film's failure to disclose that the voice's father held a post in the Hamas-administered authority was substantially inaccurate.
"Consequently that the audience did not have critical information which may have been extremely pertinent to their assessment of the presenter and the content he shared.
"Credibility is at the core of the relationship between a television network and its audience, especially for a national broadcasting corporation such as the BBC.
"This error had the potential to damage the very considerable degrees of confidence that audiences would have placed in a documentary produced by the BBC about the conflict in Gaza."
The documentary was withdrawn from the BBC's streaming service in the month of February after the presenter's family links emerged, and in the month of July an broadcaster's internal assessment found it infringed the broadcaster's content policies on factual correctness.
A BBC spokesperson said: "The Ofcom ruling is in agreement with the findings of Peter Johnston's review, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the authority's determination in complete. We will follow the sanction as soon as the date and wording are finalised."
