The BBC committed a "serious breach" of broadcasting rules by not revealing that the voice of a documentary about Gaza was the son of a Hamas official, according to British broadcasting authority Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The BBC's director general had previously apologised, saying there had been "a significant failing in relation to accuracy".
The regulator has directed the BBC to broadcast a peak-time statement about its decisions.
"As this represents a significant violation of our regulations, we are instructing the corporation to air a announcement of our findings against it on the BBC's second channel at 21:00, with a date to be finalised," the statement read.
'Possibility to Undermine Credibility'
The authority's statement stated: "Our investigation found that the documentary's failure to disclose that the voice's parent held a role in the Hamas-controlled authority was significantly deceptive.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their evaluation of the voice and the information he shared.
"Credibility is at the core of the relationship between a television network and its public, notably for a state-funded media outlet such as the BBC.
"This oversight had the possibility to damage the significantly high degrees of trust that audiences would have placed in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from the BBC's streaming service in February after the boy's family links emerged, and in July an internal BBC review determined it infringed the organization's content policies on truthfulness.
A corporation official stated: "The regulator's decision is in accordance with the conclusions of Peter Johnston's review, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on factual correctness, which reflects regulation 2.2 of the regulator's media standards.
"We have apologised for this and we accept the regulator's ruling in complete. We will follow the penalty as soon as the timing and wording are determined."
