The BBC engaged in a "significant breach" of industry standards by omitting to mention that the voice of a documentary about Gaza was the offspring of a Hamas official, as ruled by British broadcasting authority Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a major oversight in relation to truthfulness".
The regulator has directed the BBC to air a peak-time statement about its findings.
"As this represents a major infringement of our code, we are instructing the broadcaster to transmit a statement of our determinations against it on the BBC's second channel at 21:00, with a schedule to be finalised," it said.
'Potential to Damage Credibility'
The watchdog's report said: "The inquiry we conducted found that the documentary's omission to reveal that the presenter's male guardian occupied a position in the Hamas-controlled government was significantly deceptive.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their assessment of the presenter and the information he provided.
"Trust is at the center of the relationship between a broadcaster and its audience, particularly for a state-funded media outlet such as the BBC.
"This oversight had the possibility to erode the exceptionally strong levels of credibility that audiences would have placed in a documentary produced by the BBC about the Gaza conflict."
The documentary was withdrawn from the BBC's streaming service in the month of February after the boy's familial connections emerged, and in the month of July an corporation's own inquiry found it breached the broadcaster's editorial guidelines on truthfulness.
A representative for the broadcaster said: "The Ofcom ruling is in agreement with the results of the corporation's inquiry, that there was a serious error in the programme in relation to the BBC's Editorial Guidelines on accuracy, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the regulator's ruling in complete. We will adhere to the sanction as soon as the timing and language are determined."
