The public service broadcaster committed a "significant breach" of broadcasting rules by failing to disclose that the narrator of a programme about Gaza was the offspring of a Hamas administrator, 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 "substantially inaccurate".
The head of the BBC had already issued an apology, saying there had been "a significant failing in relation to accuracy".
Ofcom has instructed the broadcaster to transmit a peak-time statement about its conclusions.
"Given this constitutes a major infringement of our code, we are instructing the broadcaster to air a statement of our conclusions against it on the BBC's second channel at nine o'clock in the evening, with a date to be finalised," it said.
'Potential to Damage Credibility'
The watchdog's statement said: "Our investigation found that the film's omission to reveal that the voice's father occupied a role in the Hamas-administered administration was significantly deceptive.
"Consequently that the audience did not have essential details which may have been extremely pertinent to their judgment of the presenter and the content he shared.
"Trust is at the core of the relationship between a television network and its public, notably for a state-funded media outlet such as the BBC.
"This failing had the potential to undermine the exceptionally strong amounts of confidence that the public would have placed in a factual film from the broadcaster about the Israel-Gaza war."
The programme was pulled from iPlayer in February after the presenter's family links came to light, and in July an corporation's own inquiry found it breached the broadcaster's content policies on factual correctness.
A BBC spokesperson commented: "The Ofcom ruling is in accordance with the conclusions of Peter Johnston's review, that there was a major oversight in the documentary in relation to the corporation's content standards on factual correctness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with the authority's determination in its entirety. We will comply with the sanction as soon as the timing and wording are determined."
