The public service broadcaster engaged in a "major breach" of industry standards by not revealing that the narrator of a film about the Gaza situation was the offspring of a Hamas official, as determined by British broadcasting authority Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a serious error in relation to accuracy".
Ofcom has instructed the corporation to transmit a prime-time statement about its decisions.
"Since this amounts to a major infringement of our rules, we are instructing the broadcaster to air a message of our conclusions against it on BBC2 at 9pm, with a date to be determined," the statement read.
'Risk to Damage Credibility'
The watchdog's report declared: "The inquiry we conducted found that the documentary's omission to reveal that the narrator's parent served in a role in the Hamas-run administration was materially misleading.
"Consequently that the viewers did not have critical information which may have been extremely pertinent to their evaluation of the presenter and the information he provided.
"Confidence is at the heart of the bond between a broadcaster and its audience, especially for a state-funded media outlet such as the British Broadcasting Corporation.
"This error had the possibility to erode the very considerable amounts of trust that audiences would have invested in a documentary produced by the BBC about the conflict in Gaza."
The programme was withdrawn from the online platform in February after the presenter's personal associations came to light, and in this past July an internal BBC review found it breached the corporation's editorial guidelines on accuracy.
A BBC spokesperson stated: "The authority's determination is in line with the results of Peter Johnston's review, that there was a major oversight in the programme in relation to the broadcaster's journalistic policies on accuracy, which reflects clause 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we accept the regulator's ruling in its entirety. We will follow the penalty as soon as the timing and language are determined."
