The BBC engaged in a "major breach" of broadcasting rules by not revealing that the presenter of a film about the Gaza conflict was the offspring of a Hamas official, as ruled by UK media regulator Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the film was "materially misleading".
The chief executive of the broadcaster had already issued an apology, stating there had been "a major oversight in relation to factual correctness".
The regulator has instructed the corporation to air a evening declaration about its findings.
"Given this constitutes a significant violation of our rules, we are ordering the broadcaster to broadcast a message of our findings against it on the BBC's second channel at 21:00, with a date to be finalised," it said.
'Risk to Undermine Credibility'
The regulator's report stated: "Our probe determined that the programme's omission to reveal that the presenter's father occupied a post in the Hamas-controlled authority was substantially inaccurate.
"This implied that the public did not have critical information which may have been highly relevant to their judgment of the voice and the details he shared.
"Trust is at the heart of the relationship between a media organization and its public, notably for a public service broadcaster such as the BBC.
"This error had the potential to undermine the significantly high amounts of confidence that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was withdrawn from the online platform in February after the presenter's family links were revealed, and in the month of July an corporation's own inquiry found it infringed the broadcaster's content policies on factual correctness.
A corporation official said: "The authority's determination is in line with the results of Peter Johnston's review, that there was a significant failing in the film in relation to the corporation's content standards on accuracy, which corresponds to 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 directive as soon as the timing and wording are determined."
