The BBC was found to have committed a "serious breach" of broadcasting rules by not revealing that the narrator of a film about the Gaza conflict was the child of a Hamas official, according to UK media regulator Ofcom.
An probe by Ofcom into the documentary titled Gaza: How to Survive a Warzone has found that the programme was "materially misleading".
The head of the BBC had earlier expressed regret, noting there had been "a serious error in relation to accuracy".
Ofcom has ordered the broadcaster to transmit a evening declaration about its conclusions.
"As this represents a significant violation of our regulations, we are ordering the corporation to broadcast a statement of our determinations against it on the BBC's second channel at 21:00, with a timing to be determined," it said.
'Possibility to Damage Credibility'
The authority's report stated: "The inquiry we conducted found that the programme's failure to disclose that the narrator's parent occupied a post in the Hamas-administered government was materially misleading.
"It meant that the viewers did not have essential details which may have been highly relevant to their evaluation of the voice and the details he provided.
"Credibility is at the core of the connection between a broadcaster and its public, notably for a public service broadcaster such as the British Broadcasting Corporation.
"This oversight had the potential to erode the very considerable levels of confidence that the public would have placed in a factual film from the broadcaster about the conflict in Gaza."
The programme was pulled from iPlayer in February after the boy's personal associations emerged, and in July an internal BBC review concluded it breached the broadcaster's journalistic standards on accuracy.
A BBC spokesperson stated: "The Ofcom ruling is in agreement 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 reflects Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept Ofcom's decision in complete. We will follow the penalty as soon as the schedule and wording are determined."
