The BBC was found to have committed a "major breach" of broadcasting rules by omitting to mention that the presenter of a programme about the Gaza situation was the offspring of a Hamas official, according to regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had previously apologised, saying there had been "a significant failing in relation to accuracy".
The regulator has instructed the broadcaster to broadcast a prime-time announcement about its findings.
"As this represents a serious breach of our rules, we are ordering the BBC to air a announcement of our conclusions against it on BBC2 at nine o'clock in the evening, with a date to be finalised," it said.
'Potential to Damage Confidence'
The watchdog's statement said: "The inquiry we conducted concluded that the programme's lack of disclosure that the presenter's parent held a role in the Hamas-run authority was materially misleading.
"It meant that the audience did not have essential details 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, particularly for a national broadcasting corporation such as the BBC.
"This failing had the risk to undermine the exceptionally strong levels of trust that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The programme was withdrawn from the online platform in February after the boy's personal associations were revealed, and in this past July an internal BBC review found it violated the corporation's journalistic standards on truthfulness.
A BBC spokesperson said: "The Ofcom ruling is in accordance with the results of the corporation's inquiry, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the authority's determination in its entirety. We will follow the sanction as soon as the date and wording are finalised."
