Laura Kuenssberg has apologised for wrongly tweeting that a Labour activist punched a Tory advisor outside a hospital in Leeds.
The BBC News political editor deleted an initial tweet in which she claimed one of health minister Matt Hancock’s staff was punched by a protester.
But video footage soon emerged which showed nothing more than the advisor brushing into the man’s arm.
ITV’s political editor, Robert Peston, also apologised, tweeting that he was briefed by senior Tories that one of their staff had been punched.
Ms Kuenssberg tweeted: “Happy to apologise for earlier confusion about the punch that wasn’t a punch outside Leeds General - 2 sources suggested it had happened but clear from video that was wrong.”
In her deleted tweet, she had written: “So Matt Hancock was despatched to Leeds General (sorry not just Leeds Hospital) to try to sort out mess, hearing Labour activists scrambled to go and protest, and it turned nasty when they arrived - one of them punched Hancock’s adviser.”
She later wrote: “Have video from Hancock leaving Leeds General just come through so you can see for yourself - doesn’t look like punch thrown, rather, one of Tory team walks into protestor’s arm, pretty grim encounter.”
The BBC refused to comment on Ms Kuenssberg’s apology.
Mr Peston wrote on Twitter: “It is completely clear from video footage that @MattHancock's adviser was not whacked by a protestor, as I was told by senior Tories, but that he inadvertently walked into a protestor's hand. I apologise for getting this wrong.”
Mr Hancock was at Leeds General Infirmary where four-year-old Jack Williment-Barr had been pictured lying on a floor because of a lack of hospital beds.
Prime Minister Boris Johnson was criticised for his response to the photo in an interview with ITV, in which he refused to look at the image displayed on the reporter’s phone and apparently took the device and put it in his pocket.
Labour said: “The Tories are so desperate to distract from a four-year-old boy sleeping on a hospital floor because of their cuts to the NHS that, once again, they have resorted to barefaced lying.”
Ms Kuenssberg and Mr Peston have previously been criticised in the media for their haste in publishing tweets.
In October, journalist and broadcaster Peter Oborne wrote in openDemocracy that Ms Kuenssberg is “open to the criticism that she was being manipulated by Downing Street”.
Mr Oborne added: “British political journalists have got chillingly close to providing the same service to Boris Johnson that Fox News delivers for Donald Trump.
“This compliance is part of a pattern. Political editors are so pleased to be given ‘insider’ or ‘exclusive’ information that they report it without challenge or question.”
Last month, The Guardian’s Roy Greenslade wrote that Ms Kuenssberg is “wearing out her fingers with incessant tweeting”.
Speaking about political journalists such as Ms Kuenssberg and Mr Peston, he added: “In their haste to tweet they also fall into the trap of repeating briefings before they’ve had the chance to feed them through their own journalistic filter.”
Speaking about the false reports of a punch being thrown, justice secretary Robert Buckland BBC Radio 4’s Today programme on Tuesday: "I don't know who briefed what to whom and I have seen the footage.
“What I saw was a very confusing scene of public disorder.
"People who had clearly organised themselves to come along, create trouble and mischief, the sort of disorderly conduct I'm afraid from the left that we've seen in this campaign.