The British broadcaster engaged in a "serious breach" of industry standards by failing to disclose that the narrator of a film about the Gaza situation was the offspring of a Hamas official, according to regulatory body Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has found that the programme was "materially misleading".
The head of the BBC had already issued an apology, saying there had been "a major oversight in relation to factual correctness".
The authority has instructed the BBC to broadcast a peak-time announcement about its findings.
"Since this amounts to a significant violation of our rules, we are ordering the broadcaster to air a announcement of our conclusions against it on BBC2 at 21:00, with a timing to be determined," the statement read.
'Possibility to Damage Confidence'
The watchdog's report declared: "The inquiry we conducted concluded that the film's omission to reveal that the voice's male guardian occupied a post in the Hamas-run government was substantially inaccurate.
"It meant that the public did not have vital facts which may have been very significant to their evaluation of the voice and the information he presented.
"Credibility is at the core of the connection between a broadcaster and its viewers, notably for a public service broadcaster such as the public broadcaster.
"This oversight had the potential to erode the very considerable degrees of confidence that viewers would have put in a factual film from the broadcaster about the Gaza conflict."
The documentary was removed from iPlayer in last February after the presenter's personal associations were revealed, and in July an broadcaster's internal assessment determined it breached the organization's editorial guidelines on factual correctness.
A corporation official said: "The regulator's decision is in line with the conclusions of the internal assessment, that there was a significant failing in the film in relation to the corporation's content standards on factual correctness, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the authority's determination in full. We will comply with the penalty as soon as the date and language are finalised."
