The British broadcaster committed a "serious breach" of broadcasting rules by not revealing that the presenter of a film about the Gaza situation was the child of a Hamas official, as determined by British broadcasting authority Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The BBC's director general had already issued an apology, stating there had been "a major oversight in relation to factual correctness".
Ofcom has instructed the corporation to broadcast a evening announcement about its conclusions.
"Since this amounts to a serious breach of our code, we are instructing the broadcaster to air a message of our determinations against it on the BBC's second channel at nine o'clock in the evening, with a date to be finalised," the statement read.
'Risk to Damage Credibility'
The watchdog's report said: "Our probe determined that the documentary's omission to reveal that the narrator's male guardian served in a post in the Hamas-administered authority was materially misleading.
"This implied that the audience did not have critical information which may have been extremely pertinent to their judgment of the presenter and the information he shared.
"Confidence is at the core of the connection between a media organization and its public, particularly for a state-funded media outlet such as the BBC.
"This error had the potential to damage the significantly high degrees of trust that the public would have invested in a documentary produced by the BBC about the Gaza conflict."
The documentary was removed from iPlayer in the month of February after the presenter's familial connections were revealed, and in this past July an corporation's own inquiry found it infringed the broadcaster's journalistic standards on factual correctness.
A BBC spokesperson said: "The authority's determination is in line with the results 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 Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we comply with Ofcom's decision in its entirety. We will follow the sanction as soon as the schedule and wording are confirmed."
