The BBC engaged in a "major breach" of industry standards by omitting to mention that the voice of a film about Gaza was the son of a Hamas administrator, according to British broadcasting authority Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The chief executive of the broadcaster had already issued an apology, noting there had been "a major oversight in relation to accuracy".
Ofcom has instructed the BBC to air a evening declaration about its decisions.
"As this represents a serious breach of our code, we are ordering the BBC to transmit a message of our conclusions against it on the BBC's second channel at 9pm, with a timing to be confirmed," it said.
'Potential to Damage Trust'
The watchdog's statement said: "The inquiry we conducted found that the documentary's omission to reveal that the voice's father served in a role in the Hamas-administered authority was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been highly relevant to their judgment of the voice and the information he provided.
"Trust is at the center of the connection between a television network and its public, notably for a public service broadcaster such as the BBC.
"This oversight had the possibility to damage the significantly high degrees of credibility that viewers would have placed in a BBC factual programme about the Israel-Gaza war."
The film was pulled from the online platform in last February after the presenter's familial connections came to light, and in this past July an corporation's own inquiry found it infringed the corporation's content policies on factual correctness.
A corporation official said: "The authority's determination is in line with the findings of the corporation's inquiry, that there was a significant failing 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 expressed regret for this and we comply with the regulator's ruling in its entirety. We will follow the directive as soon as the date and language are finalised."
