The British broadcaster engaged in a "serious breach" of industry standards by not revealing that the presenter of a programme about Gaza was the child of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An inquiry by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The head of the BBC had earlier expressed regret, stating there had been "a significant failing in relation to accuracy".
Ofcom has instructed the broadcaster to broadcast a evening announcement about its conclusions.
"Given this constitutes a major infringement of our code, we are instructing the BBC to air a message of our determinations against it on the BBC's second channel at 9pm, with a date to be finalised," it said.
'Risk to Undermine Confidence'
The authority's report declared: "The inquiry we conducted concluded that the documentary's failure to disclose that the narrator's parent served in a post in the Hamas-controlled administration was substantially inaccurate.
"Consequently that the viewers did not have critical information which may have been very significant to their assessment of the presenter and the details he provided.
"Trust is at the heart of the bond between a broadcaster and its public, particularly for a state-funded media outlet such as the BBC.
"This failing had the potential to undermine the exceptionally strong levels of credibility that viewers would have put in a documentary produced by the BBC about the Gaza conflict."
The film was removed from the BBC's streaming service in last February after the presenter's personal associations were revealed, and in July an broadcaster's internal assessment concluded it breached the corporation's content policies on truthfulness.
A representative for the broadcaster stated: "The authority's determination is in agreement with the conclusions of Peter Johnston's review, that there was a significant failing in the film in relation to the BBC's Editorial Guidelines on accuracy, which reflects regulation 2.2 of the regulator's media standards.
"We have apologised for this and we comply with the authority's determination in its entirety. We will adhere to the sanction as soon as the timing and wording are determined."
