The public service broadcaster engaged in a "significant breach" of media regulations by failing to disclose that the narrator of a programme about Gaza was the offspring of a Hamas official, according to British broadcasting authority Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has determined that the documentary was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a major oversight in relation to factual correctness".
The regulator has ordered the corporation to transmit a evening declaration about its decisions.
"As this represents a significant violation of our regulations, we are instructing the BBC to broadcast a message of our conclusions against it on the BBC's second channel at 21:00, with a date to be finalised," it said.
'Possibility to Undermine Credibility'
The authority's statement stated: "Our investigation concluded that the programme's omission to reveal that the voice's male guardian held a post in the Hamas-administered government was significantly deceptive.
"This implied that the audience did not have essential details which may have been extremely pertinent to their evaluation of the presenter and the details he shared.
"Credibility is at the center of the relationship between a television network and its audience, especially for a national broadcasting corporation such as the public broadcaster.
"This oversight had the potential to undermine the exceptionally strong amounts of confidence that viewers would have placed in a BBC factual programme about the Gaza conflict."
The programme was withdrawn from the BBC's streaming service in February after the presenter's family links were revealed, and in the month of July an broadcaster's internal assessment concluded it violated the broadcaster's content policies on accuracy.
A representative for the broadcaster commented: "The Ofcom ruling is in accordance with the conclusions of Peter Johnston's review, that there was a significant failing in the documentary in relation to the corporation's content standards on truthfulness, which reflects clause 2.2 of the regulator's media standards.
"We issued an apology for this and we accept Ofcom's decision in full. We will comply with the sanction as soon as the date and wording are determined."
