The BBC was found to have committed a "serious breach" of broadcasting rules by omitting to mention that the voice of a programme about the Gaza conflict was the son of a Hamas administrator, according to regulatory body Ofcom.
An investigation by the media regulator into the programme Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The head of the BBC had previously apologised, stating there had been "a major oversight in relation to factual correctness".
The authority has directed the BBC to broadcast a evening statement about its conclusions.
"Since this amounts to a major infringement of our rules, we are directing the corporation to transmit a message of our determinations against it on BBC2 at nine o'clock in the evening, with a schedule to be confirmed," it said.
'Potential to Damage Confidence'
The regulator's announcement said: "Our investigation found that the documentary's omission to reveal that the presenter's parent served in a post in the Hamas-controlled authority was substantially inaccurate.
"Consequently that the audience did not have essential details which may have been very significant to their evaluation of the narrator and the details he presented.
"Trust is at the heart of the bond between a broadcaster and its public, notably for a public service broadcaster such as the public broadcaster.
"This error had the potential to erode the significantly high degrees of confidence that viewers would have put in a factual film from the broadcaster about the Israel-Gaza war."
The film was withdrawn from the online platform in last February after the narrator's family links emerged, and in July an corporation's own inquiry determined it violated the broadcaster's journalistic standards on truthfulness.
A corporation official stated: "The regulator's decision is in line with the results of the internal assessment, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on truthfulness, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the regulator's ruling in full. We will follow the penalty as soon as the schedule and wording are finalised."
