The BBC engaged in a "major breach" of broadcasting rules by failing to disclose that the narrator of a programme about Gaza was the offspring of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The head of the BBC had earlier expressed regret, saying there had been "a major oversight in relation to truthfulness".
The authority has instructed the corporation to broadcast a evening declaration about its conclusions.
"Given this constitutes a major infringement of our regulations, we are ordering the corporation to transmit a message of our conclusions against it on the BBC's second channel at 9pm, with a schedule to be confirmed," it said.
'Possibility to Undermine Trust'
The watchdog's report said: "Our probe concluded that the documentary's failure to disclose that the voice's parent occupied a post in the Hamas-run government was materially misleading.
"Consequently that the viewers did not have vital facts which may have been highly relevant to their evaluation of the voice and the information he provided.
"Credibility is at the heart of the bond between a broadcaster and its viewers, especially for a state-funded media outlet such as the BBC.
"This error had the risk to damage the very considerable levels of credibility that audiences would have put in a factual film from the broadcaster about the Israel-Gaza war."
The programme was withdrawn from iPlayer in February after the boy's personal associations were revealed, and in July an corporation's own inquiry determined it breached the broadcaster's editorial guidelines on truthfulness.
A corporation official commented: "The regulator's decision is in agreement with the conclusions of Peter Johnston's review, that there was a significant failing in the documentary in relation to the corporation's content standards on factual correctness, which aligns with clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept Ofcom's decision in complete. We will comply with the directive as soon as the schedule and wording are determined."
