The BBC committed a "major breach" of media regulations by omitting to mention that the voice of a programme about the Gaza situation was the child of a Hamas representative, as determined by UK media regulator Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The BBC's director general had previously apologised, noting there had been "a significant failing in relation to factual correctness".
The regulator has ordered the corporation to air a prime-time announcement about its conclusions.
"Since this amounts to a serious breach of our code, we are ordering the broadcaster to air a announcement of our conclusions against it on BBC2 at 21:00, with a date to be confirmed," it said.
'Risk to Damage Confidence'
The regulator's statement said: "Our investigation concluded that the film's failure to disclose that the voice's father served in a post in the Hamas-run government was substantially inaccurate.
"It meant that the audience did not have critical information which may have been very significant to their assessment of the voice and the information he shared.
"Credibility is at the heart of the connection between a broadcaster and its viewers, notably for a state-funded media outlet such as the BBC.
"This error had the potential to damage the exceptionally strong degrees of credibility that viewers would have invested in a documentary produced by the BBC about the Gaza conflict."
The documentary was removed from the BBC's streaming service in last February after the presenter's personal associations came to light, and in this past July an internal BBC review determined it breached the corporation's content policies on factual correctness.
A BBC spokesperson stated: "The Ofcom ruling 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 truthfulness, which reflects regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the regulator's ruling in its entirety. We will comply with the penalty as soon as the timing and wording are confirmed."
