The BBC was found to have committed a "major breach" of media regulations by not revealing that the voice of a programme about the Gaza conflict was the offspring of a Hamas administrator, according to UK media regulator Ofcom.
An investigation by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had already issued an apology, saying there had been "a significant failing in relation to truthfulness".
The authority has ordered the corporation to transmit a peak-time declaration about its findings.
"As this represents a serious breach of our regulations, we are instructing the BBC to transmit a announcement of our determinations against it on the BBC's second channel at 9pm, with a timing to be confirmed," the regulator stated.
'Risk to Erode Trust'
The watchdog's report stated: "Our investigation concluded that the programme's omission to reveal that the presenter's father served in a post in the Hamas-administered authority was materially misleading.
"It meant that the viewers did not have vital facts which may have been very significant to their judgment of the voice and the content he presented.
"Trust is at the heart of the connection between a broadcaster and its audience, notably for a public service broadcaster such as the British Broadcasting Corporation.
"This oversight had the potential to erode the very considerable levels of trust that audiences would have put in a BBC factual programme about the conflict in Gaza."
The programme was pulled from iPlayer in last February after the presenter's personal associations came to light, and in this past July an internal BBC review found it infringed the broadcaster's editorial guidelines on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in accordance with the findings of Peter Johnston's review, that there was a significant failing in the documentary in relation to the corporation's content standards on factual correctness, which reflects regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we comply with the authority's determination in full. We will follow the sanction as soon as the timing and wording are finalised."
