The public service broadcaster committed a "significant breach" of industry standards by omitting to mention that the narrator of a film about the Gaza conflict was the child of a Hamas representative, according to regulatory body Ofcom.
An probe by Ofcom into the documentary titled Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a major oversight in relation to truthfulness".
The authority has directed the broadcaster to transmit a evening declaration about its findings.
"As this represents a significant violation of our rules, we are ordering the broadcaster to transmit a message of our conclusions against it on the BBC's second channel at 9pm, with a timing to be confirmed," it said.
'Potential to Erode Credibility'
The regulator's announcement stated: "The inquiry we conducted found that the documentary's failure to disclose that the narrator's parent held a post in the Hamas-run administration was materially misleading.
"This implied that the viewers did not have essential details which may have been very significant to their judgment of the narrator and the information he presented.
"Trust is at the core of the relationship between a television network and its public, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the risk to erode the very considerable amounts of confidence that audiences would have put in a documentary produced by the BBC about the conflict in Gaza."
The programme was removed from iPlayer in last February after the narrator's familial connections emerged, and in this past July an internal BBC review concluded it breached the corporation's journalistic standards on truthfulness.
A representative for the broadcaster said: "The authority's determination is in accordance with the findings of Peter Johnston's review, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on truthfulness, which corresponds to Rule 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with the regulator's ruling in its entirety. We will comply with the penalty as soon as the schedule and language are confirmed."
