The BBC engaged in a "serious breach" of broadcasting rules by not revealing that the presenter of a documentary about the Gaza conflict was the child of a Hamas official, according to regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The head of the BBC had already issued an apology, stating there had been "a major oversight in relation to accuracy".
The regulator has instructed the corporation to air a prime-time declaration about its conclusions.
"Given this constitutes a serious breach of our regulations, we are directing the corporation to transmit a announcement of our findings against it on BBC Two at 21:00, with a timing to be determined," the regulator stated.
'Potential to Damage Trust'
The authority's statement said: "The inquiry we conducted found that the documentary's lack of disclosure that the presenter's male guardian occupied a post in the Hamas-run administration was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been extremely pertinent to their assessment of the voice and the details he provided.
"Trust is at the core of the connection between a television network and its viewers, particularly for a public service broadcaster such as the BBC.
"This error had the risk to erode the significantly high amounts of trust that viewers would have placed in a factual film from the broadcaster about the Israel-Gaza war."
The programme was pulled from the online platform in February after the boy's familial connections came to light, and in the month of July an broadcaster's internal assessment concluded it violated the corporation's journalistic standards on accuracy.
A corporation official said: "The regulator's decision is in accordance with the results of the internal assessment, that there was a serious error in the programme in relation to the BBC's Editorial Guidelines on truthfulness, which reflects regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we agree with the authority's determination in full. We will comply with the sanction as soon as the schedule and wording are confirmed."
