The public service broadcaster committed a "major breach" of media regulations by omitting to mention that the voice of a film about the Gaza situation was the son of a Hamas administrator, according to regulatory body Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The BBC's director general had earlier expressed regret, stating there had been "a significant failing in relation to factual correctness".
The regulator has ordered the broadcaster to air a prime-time statement about its conclusions.
"Since this amounts to a major infringement of our rules, we are ordering the broadcaster to transmit a message of our findings against it on BBC Two at nine o'clock in the evening, with a date to be finalised," it said.
'Possibility to Damage Trust'
The regulator's announcement said: "The inquiry we conducted concluded that the documentary's failure to disclose that the voice's parent occupied a role in the Hamas-controlled administration was significantly deceptive.
"It meant that the public did not have critical information which may have been very significant to their evaluation of the narrator and the information he provided.
"Credibility is at the core of the bond between a broadcaster and its viewers, especially for a state-funded media outlet such as the BBC.
"This failing had the potential to damage the significantly high levels of credibility that viewers would have put in a factual film from the broadcaster about the conflict in Gaza."
The documentary was removed from the BBC's streaming service in the month of February after the presenter's family links emerged, and in this past July an broadcaster's internal assessment concluded it violated the corporation's content policies on truthfulness.
A corporation official commented: "The authority's determination is in accordance with the results of Peter Johnston's review, that there was a major oversight in the programme in relation to the corporation's content standards on accuracy, which aligns with clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we comply with Ofcom's decision in full. We will comply with the directive as soon as the date and wording are determined."
