The BBC committed a "serious breach" of broadcasting rules by omitting to mention that the presenter of a documentary about Gaza was the child of a Hamas representative, according to British broadcasting authority Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "substantially inaccurate".
The BBC's director general had already issued an apology, noting there had been "a major oversight in relation to accuracy".
The regulator has ordered the corporation to transmit a peak-time announcement about its decisions.
"As this represents a serious breach of our code, we are directing the BBC to broadcast a announcement of our conclusions against it on BBC Two at nine o'clock in the evening, with a timing to be confirmed," it said.
'Possibility to Erode Credibility'
The authority's report stated: "Our investigation determined that the documentary's failure to disclose that the presenter's parent held a role in the Hamas-controlled government was materially misleading.
"This implied that the audience did not have critical information which may have been extremely pertinent to their evaluation of the voice and the information he shared.
"Trust is at the core of the relationship between a television network and its public, especially for a national broadcasting corporation such as the BBC.
"This error had the potential to undermine the significantly high degrees of credibility that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was removed from the BBC's streaming service in February after the presenter's family links came to light, and in the month of July an broadcaster's internal assessment determined it violated the broadcaster's journalistic standards on factual correctness.
A representative for the broadcaster stated: "The authority's determination is in line with the findings of the internal assessment, that there was a serious error in the programme in relation to the broadcaster's journalistic policies on factual correctness, which corresponds to Rule 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 date and wording are determined."
