ITV has been found in breach of broadcasting rules for mistakenly claiming that a scene from a video game was footage of an IRA attack.

Viewers complained to Ofcom after the programme, Exposure: Gaddafi And The IRA, described the footage as IRA film of IRA members attempting to shoot down a British Army helicopter in 1988.

ITV later confirmed that the footage was taken from the internet, and was in fact from the video game Arma 2.

A further blunder occurred when the same programme, which examined the links between former Libyan leader Colonel Gaddafi and the IRA, showed footage of police clashing with rioters.

The programme, broadcast in September last year, described the scene as a riot in Ardoyne in Belfast in July 2011.

Eagle-eyed viewers spotted that the type of police vehicles seen in the footage showed that it must have been an earlier riot.

Ofcom said that it was "very surprised" that programme-makers believed the helicopter attack footage was genuine.

It said that it was "concerned" that ITV failed to take proper steps to check both pieces of footage.

"The viewers of this serious current affairs programme were misled as to the nature of the material they were watching," it said.

"This represented a significant breach of audience trust, particularly in the context of a public service broadcaster."

Programme-makers ended up using the video game scene after attempting to find a fuller version of footage used in 1989 in investigative programme The Cook Report.

The programme's director believed he had found the material when he viewed footage from the internet.

"Although there were clear differences between the two pieces of footage, his memory over the ensuing period of time let him down and led him to believe it was the same footage", ITV said.

A compliance team member, concerned about the sound effects and pictures in the clip, asked if it "really did depict" the shooting down of a British Army helicopter in June 1988.

"Neither the producer nor the director ever cross-checked the internet footage with the Cook Report footage", despite the producer assuring the compliance member that it was genuine.

In the second mistake, ITV obtained footage from a local historian considered a trustworthy source.

ITV said that the clip, of what turned out to be an earlier riot, was aired because of a "miscommunication" between the producer and the historian.

ITV apologised and said that the mistakes were the result of human error, and that it had not intended to mislead viewers.

Ofcom said that it had taken into account the apology, the removal of the programme from ITV's catch-up service, and changes made to its compliance procedures.

But it said: "There were significant and easily identifiable differences between the footage of the attack on the helicopter included in the 1989 Cook Report and the footage taken from the internet from the video game Arma 2."

"It is not sufficient for a broadcaster or programme-maker to rely on footage provided by a third-party source, on the basis that that source had previously supplied other broadcasters with archive footage, and fail to confirm the details of archive film provided", it said.

It warned that it was "particularly concerned by this compliance failure by ITV," stating: "We do not expect any issues of a similar nature to arise in future."

The programme was found to be "materially misleading", and in breach of the broadcasting code.