The BBC committed a “serious breach” of broadcasting rules by failing to disclose that the narrator of a documentary on Gaza was the son of a Hamas official, Britain’s media regulator Ofcom has ruled.

An Ofcom investigation into the documentary Gaza: How to Survive a Warzone concluded that it was “materially misleading”.

The director-general of the BBC had previously apologised, saying there had been a “significant lapse in accuracy”.

Ofcom ordered the BBC to broadcast a prime-time announcement about its findings.

“As this is a serious breach of our rules, we are directing the BBC to broadcast a statement of our findings against him on BBC 2 at 9pm on a date to be confirmed,” it said.

“Possibility of erosion of trust”

The watchdog’s statement said: “Our investigation found that the show’s failure to disclose that the narrator’s father held a position in the Hamas-run government was substantially misleading.

“This meant that the audience was missing out on critical information that might be highly relevant to their evaluation of the narrator and the information he was providing.

“Trust is at the heart of the relationship between a broadcaster and its audience, particularly for a public broadcaster like the BBC.

“This failure had the potential to erode the significantly high levels of trust that the public would place in a factual BBC program about the Israel-Gaza war.”

The documentary was pulled from iPlayer in February after the boy’s family links were revealed, and in July an internal BBC review found it breached the company’s journalistic guidelines on accuracy.

A BBC spokesman said: “Ofcom’s decision is in line with the findings of Peter Johnston’s assessment that there was a significant failure in the documentary in relation to the BBC’s Editorial Guidelines on Accuracy, which reflect Rule 2.2 of Ofcom’s Broadcasting Code.

“We have apologized for this and fully accept Ofcom’s decision. We will comply with the sanction once the date and wording are finalised.”