The public service broadcaster engaged in a "major breach" of industry standards by not revealing that the voice of a documentary about the Gaza conflict was the child of a Hamas administrator, according to British broadcasting authority Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The chief executive of the broadcaster had already issued an apology, saying there had been "a serious error in relation to accuracy".
Ofcom has ordered the BBC to transmit a evening announcement about its decisions.
"Given this constitutes a major infringement of our code, we are instructing the broadcaster to broadcast a announcement of our findings against it on the BBC's second channel at 9pm, with a timing to be determined," it said.
'Risk to Undermine Trust'
The watchdog's statement said: "The inquiry we conducted determined that the documentary's failure to disclose that the narrator's male guardian held a post in the Hamas-administered administration was materially misleading.
"This implied that the viewers did not have essential details which may have been very significant to their evaluation of the presenter and the information he shared.
"Trust is at the core of the connection between a broadcaster and its audience, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the possibility to erode the very considerable amounts of confidence that viewers would have placed in a factual film from the broadcaster about the Gaza conflict."
The programme was withdrawn from the online platform in the month of February after the narrator's personal associations came to light, and in July an internal BBC review concluded it breached the corporation's journalistic standards on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in agreement with the conclusions of Peter Johnston's review, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on accuracy, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we accept the regulator's ruling in complete. We will comply with the penalty as soon as the schedule and language are determined."
