The BBC was found to have committed a "major breach" of industry standards by omitting to mention that the presenter of a documentary about the Gaza conflict was the son of a Hamas representative, as ruled by regulatory body Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The BBC's director general had previously apologised, noting there had been "a serious error in relation to truthfulness".
Ofcom has ordered the broadcaster to broadcast a prime-time declaration about its decisions.
"Since this amounts to a significant violation of our rules, we are ordering the broadcaster to broadcast a message of our determinations against it on BBC2 at 9pm, with a timing to be determined," it said.
'Risk to Undermine Credibility'
The regulator's statement stated: "Our investigation found that the documentary's lack of disclosure that the narrator's male guardian served in a role in the Hamas-run authority was substantially inaccurate.
"This implied that the audience did not have critical information which may have been very significant to their evaluation of the voice and the information he shared.
"Credibility is at the center of the connection between a television network and its public, especially for a state-funded media outlet such as the BBC.
"This failing had the risk to undermine the very considerable degrees of credibility that the public would have invested in a factual film from the broadcaster about the conflict in Gaza."
The programme was removed from the BBC's streaming service in last February after the presenter's family links were revealed, and in this past July an broadcaster's internal assessment concluded it infringed the broadcaster's journalistic standards on accuracy.
A corporation official said: "The authority's determination is in accordance with the conclusions of Peter Johnston's review, that there was a serious error in the film in relation to the corporation's content standards on factual correctness, which reflects regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we accept the authority's determination in its entirety. We will comply with the directive as soon as the date and wording are finalised."
