The BBC engaged in a "major breach" of broadcasting rules by not revealing that the narrator of a programme about Gaza was the child of a Hamas representative, as ruled by UK media regulator Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a significant failing in relation to accuracy".
Ofcom has ordered the broadcaster to air a prime-time statement about its findings.
"Since this amounts to a significant violation of our regulations, we are instructing the broadcaster to transmit a message of our conclusions against it on BBC Two at 9pm, with a timing to be determined," it said.
'Possibility to Damage Trust'
The watchdog's announcement declared: "Our investigation determined that the programme's lack of disclosure that the voice's father occupied a position in the Hamas-run authority was materially misleading.
"Consequently that the viewers did not have vital facts which may have been highly relevant to their evaluation of the voice and the information he presented.
"Credibility is at the center of the connection between a broadcaster and its viewers, particularly for a public service broadcaster such as the public broadcaster.
"This failing had the risk to erode the very considerable amounts of trust that the public would have invested in a factual film from the broadcaster about the conflict in Gaza."
The documentary was pulled from iPlayer in the month of February after the presenter's familial connections came to light, and in this past July an corporation's own inquiry concluded it infringed the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson said: "The regulator's decision is in accordance with the results of the corporation's inquiry, that there was a major oversight in the programme in relation to the BBC's Editorial Guidelines on accuracy, which reflects clause 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the regulator's ruling in its entirety. We will comply with the penalty as soon as the schedule and wording are finalised."
