The public service broadcaster committed a "major breach" of broadcasting rules by omitting to mention that the presenter of a programme about the Gaza conflict was the son of a Hamas official, as determined by regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The BBC's director general had previously apologised, noting there had been "a significant failing in relation to truthfulness".
The authority has instructed the corporation to transmit a evening declaration about its conclusions.
"As this represents a major infringement of our code, we are ordering the corporation to air a message of our conclusions against it on BBC2 at 21:00, with a date to be determined," the regulator stated.
'Potential to Damage Trust'
The watchdog's statement stated: "Our probe found that the film's omission to reveal that the presenter's parent occupied a role in the Hamas-controlled administration was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been extremely pertinent to their judgment of the narrator and the content he provided.
"Confidence is at the core of the bond between a television network and its public, especially for a state-funded media outlet such as the British Broadcasting Corporation.
"This error had the risk to undermine the significantly high degrees of credibility that viewers would have placed in a documentary produced by the BBC about the Gaza conflict."
The programme was pulled from iPlayer in last February after the narrator's personal associations emerged, and in the month of July an corporation's own inquiry determined it violated the corporation's journalistic standards on truthfulness.
A representative for the broadcaster said: "The regulator's decision is in accordance with the findings of the internal assessment, that there was a serious error in the programme in relation to the BBC's Editorial Guidelines on truthfulness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we agree with Ofcom's decision in complete. We will adhere to the sanction as soon as the schedule and language are finalised."
