The public service broadcaster engaged in a "significant breach" of broadcasting rules by omitting to mention that the voice of a film about Gaza was the offspring of a Hamas representative, according to British broadcasting authority Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The head of the BBC had previously apologised, noting there had been "a major oversight in relation to accuracy".
The authority has directed the broadcaster to transmit a evening statement about its findings.
"Given this constitutes a serious breach of our rules, we are instructing the corporation to transmit a message of our determinations against it on BBC Two at 21:00, with a date to be determined," the statement read.
'Possibility to Erode Trust'
The watchdog's announcement declared: "Our investigation determined that the film's omission to reveal that the presenter's father held a post in the Hamas-run government was materially misleading.
"It meant that the public did not have vital facts which may have been very significant to their evaluation of the presenter and the information he provided.
"Confidence is at the center of the connection between a media organization and its public, especially for a public service broadcaster such as the public broadcaster.
"This oversight had the possibility to erode the significantly high amounts of trust that the public would have placed in a documentary produced by the BBC about the conflict in Gaza."
The film was pulled from iPlayer in February after the presenter's familial connections came to light, and in the month of July an internal BBC review concluded it infringed the organization's journalistic standards on truthfulness.
A representative for the broadcaster said: "The regulator's decision is in agreement with the results of Peter Johnston's review, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which reflects Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the regulator's ruling in its entirety. We will adhere to the sanction as soon as the date and wording are finalised."
