The BBC was found to have committed a "serious breach" of broadcasting rules by not revealing that the presenter of a programme about the Gaza situation was the child of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An investigation by the media regulator into the programme Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had earlier expressed regret, noting there had been "a significant failing in relation to truthfulness".
Ofcom has ordered the corporation to air a evening announcement about its decisions.
"As this represents a major infringement of our code, we are directing the corporation to air a announcement of our findings against it on BBC Two at 9pm, with a timing to be determined," it said.
'Possibility to Erode Credibility'
The watchdog's announcement declared: "The inquiry we conducted found that the programme's failure to disclose that the presenter's parent held a post in the Hamas-administered authority was materially misleading.
"Consequently that the audience did not have critical information which may have been highly relevant to their judgment of the presenter and the content he provided.
"Trust is at the core of the bond between a media organization and its public, notably for a national broadcasting corporation such as the public broadcaster.
"This error had the possibility to undermine the very considerable degrees of trust that viewers would have invested in a BBC factual programme about the Gaza conflict."
The programme was withdrawn from iPlayer in the month of February after the presenter's personal associations came to light, and in the month of July an internal BBC review found it breached the organization's content policies on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in accordance with the conclusions of the corporation's inquiry, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which reflects Rule 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the regulator's ruling in full. We will comply with the penalty as soon as the schedule and wording are finalised."
