The British broadcaster engaged in a "major breach" of broadcasting rules by failing to disclose that the voice of a film about the Gaza conflict was the offspring of a Hamas official, as determined by regulatory body Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a significant failing in relation to truthfulness".
The regulator has ordered the corporation to transmit a evening declaration about its decisions.
"Given this constitutes a significant violation of our rules, we are directing the corporation to transmit a message of our conclusions against it on BBC Two at nine o'clock in the evening, with a schedule to be finalised," it said.
'Risk to Damage Confidence'
The watchdog's report stated: "The inquiry we conducted concluded that the documentary's omission to reveal that the presenter's parent held a role in the Hamas-run authority was substantially inaccurate.
"It meant that the public did not have essential details which may have been highly relevant to their judgment of the narrator and the content he presented.
"Confidence is at the center of the bond between a television network and its audience, notably for a national broadcasting corporation such as the British Broadcasting Corporation.
"This oversight had the risk to damage the exceptionally strong amounts of trust that audiences would have placed in a factual film from the broadcaster about the Israel-Gaza war."
The programme was withdrawn from iPlayer in last February after the presenter's familial connections emerged, and in July an internal BBC review determined it violated the broadcaster's journalistic standards on truthfulness.
A corporation official commented: "The regulator's decision is in accordance with the conclusions of Peter Johnston's review, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on truthfulness, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with Ofcom's decision in its entirety. We will adhere to the sanction as soon as the schedule and language are determined."
