Channel 4 News has been ordered to broadcast a lengthy on-air correction after it identified the wrong man as the terrorist involved in an attack on parliament in March.
The programme told viewers Abu Izzadeen, also known as Trevor Brooks, who was found guilty of terrorist fundraising and inciting terrorism overseas in 2008, was the man who drove a car into pedestrians on Westminster Bridge before fatally stabbing a police officer in parliament and being shot dead by security guards.
In reality Izzadeen was very much alive and in prison at the time of the offence, which was actually carried out by Khalid Masood.
TV regulator Ofcom said it was a "serious breach" of its rules on accurate reporting to wrongly accuse someone of committing mass murder and concluded that the programme's editor decided to circumvent established procedures in order to get the story on air.
"We acknowledge that breaking news requires editorial teams to make decisions rapidly while under intense pressure," said Ofcom. "However, Channel 4 News’ rush to get this story to air resulted in it broadcasting a significant error on a major news story."
Channel 4 News ran the story based on a single source after Izzadeen's name began circling on Twitter as the potential identity of the attacker.
According to Ofcom's account of events, a journalist in the newsroom flagged the social media speculation to the programme editor at around 5.30pm on the afternoon of the attack.
At 6.30pm – just 30 minutes before Channel 4 News goes on air – the programme editor and managing editor asked its experienced home affairs correspondent Simon Israel to check whether the name was correct.
At this point Israel was, according to Ofcom's report, "unaware that the newsroom had been researching this matter; had no knowledge that Abu Izzadeen was being named as the potential attacker; and was not informed that there were any doubts over the veracity of the story".
Israel contacted two sources, one of which said they did not know and another who said they believed Izzadeen was the suspect.
Channel 4 News' editor then decided the single source was sufficiently reliable. With just moments to go before broadcast, the decision was made to press ahead and due to time constraints "it did not prove possible to corroborate the information with other sources".
As a result Israel opened the broadcast by declaring that Channel 4 News had learned "from a very reliable source" that Izzadeen was the terrorist involved in the attack. Although some statements during the programme qualified the sourcing on his identity, others declared him to definitively be the attacker.
Izzadeen's alleged involvement was then discussed at length, although doubts about the story's accuracy soon began to surface.
By the end of the hour-long programme presenter Jon Snow was already telling viewers the story might be wrong: "We’ve got a little bit more on this fast-developing story about today’s attack in Westminster. Channel 4 News has been contacted by Abu Izzadeen’s brother, who tells this programme that he is in fact still serving a prison sentence. That from Yusuf Brooks, brother of Trevor Brooks, also known as Abu Izzadeen."
Despite the on-air apology and subsequent public corrections Ofcom concluded that it was significantly inaccurate to spend 35 minutes of the programme claiming "that Abu Izzadeen was responsible for multiple killings, murdering a police officer and carrying out the attack".
Channel 4 News told Ofcom that there is an established procedure for dealing with such stories, which involves sending them to the top level of management.
"However, because of the time pressure, with the absolute final decision taken to run the story literally minutes before going to air (at 18:56), the editor believed that such a referral would have been simply impracticable."
As a result the regulator concluded the editor acted with "substantial risk" by choosing to press ahead with the story.
Ofcom found journalists in the newsroom were aware of the potential misidentification even before the programme went to air but did not inform the correspondent.
While Ofcom acknowledged that the broadcaster immediately issued corrections and pulled repeat broadcasts it found "this inaccuracy was of such magnitude and given such prominence that it was not fully mitigated by the later steps".
Other news outlets soon followed Channel 4's lead, with sites such as The Independent also falsely naming Izzadeen on the basis of the broadcaster's single-sourced report and then later deleting its story.
A spokesperson for Channel 4 News confirmed to BuzzFeed News that no one would leave their jobs as a result of the error, which is the programme's fourth breach of the broadcasting code in the last three years.
Ofcom said it was "particularly concerned that a further serious breach" had occurred in circumstances where the programme didn't follow its own referral procedures for referring anonymous single source stories to top levels of management.
A spokesperson for Channel 4 News said: "Channel 4 News takes its obligations under the Ofcom Broadcasting Code extremely seriously and is committed to providing audiences with high-quality, accurate and impartial news programming. We have participated fully in Ofcom’s investigation and note the regulator’s ruling which takes into account the immediate steps taken to correct and clarify the error during the course of the programme."