The BBC engaged in a "significant breach" of media regulations by omitting to mention that the presenter of a film about the Gaza situation was the child of a Hamas administrator, as ruled by British broadcasting authority Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had already issued an apology, saying there had been "a significant failing in relation to truthfulness".
The authority has instructed the BBC to transmit a prime-time declaration about its conclusions.
"Since this amounts to a serious breach of our code, we are instructing the broadcaster to broadcast a message of our conclusions against it on BBC Two at 21:00, with a schedule to be finalised," the regulator stated.
'Risk to Erode Credibility'
The watchdog's announcement said: "Our investigation determined that the documentary's lack of disclosure that the narrator's parent served in a post in the Hamas-controlled administration was significantly deceptive.
"This implied that the viewers did not have critical information which may have been very significant to their evaluation of the presenter and the details he presented.
"Credibility is at the center of the relationship between a broadcaster and its viewers, notably for a public service broadcaster such as the BBC.
"This failing had the potential to undermine the significantly high degrees of confidence that viewers would have placed in a factual film from the broadcaster about the Gaza conflict."
The programme was pulled from the online platform in February after the narrator's familial connections emerged, and in the month of July an corporation's own inquiry found it breached the broadcaster's editorial guidelines on factual correctness.
A BBC spokesperson stated: "The authority's determination is in accordance with the results of the internal assessment, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on accuracy, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with the regulator's ruling in full. We will adhere to the directive as soon as the schedule and language are finalised."
