The BBC committed a "significant breach" of broadcasting rules by not revealing that the voice of a film about the Gaza conflict was the child of a Hamas official, as ruled by British broadcasting authority Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The head of the BBC had previously apologised, saying there had been "a serious error in relation to truthfulness".
Ofcom has ordered the corporation to broadcast a peak-time declaration about its conclusions.
"As this represents a major infringement of our code, we are instructing the broadcaster to air a statement of our determinations against it on BBC Two at 21:00, with a schedule to be finalised," the regulator stated.
'Possibility to Erode Trust'
The regulator's statement declared: "The inquiry we conducted found that the documentary's omission to reveal that the presenter's father occupied a role in the Hamas-run authority was significantly deceptive.
"It meant that the audience did not have essential details which may have been highly relevant to their evaluation of the presenter and the content he shared.
"Confidence is at the core of the connection between a television network and its viewers, especially for a state-funded media outlet such as the public broadcaster.
"This failing had the risk to damage the significantly high levels of confidence that viewers would have placed in a documentary produced by the BBC about the Israel-Gaza war."
The documentary was removed from the BBC's streaming service in the month of February after the boy's family links emerged, and in July an broadcaster's internal assessment found it infringed the broadcaster's editorial guidelines on truthfulness.
A corporation official commented: "The Ofcom ruling is in line with the findings of the internal assessment, that there was a serious error in the programme in relation to the corporation's content standards on accuracy, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we agree with Ofcom's decision in full. We will follow the penalty as soon as the schedule and wording are determined."
