A false news story claiming that a Labour activist punched a Tory advisor has spread across social media after being amplified by some of the country's leading political journalists.

But the police have confirmed that there are no reports of any incident taking place, and video appears to show that the supposed punch was actually an advisor walking into a protestor's hand.

The incident happened after health secretary Matthew Hancock was dispatched to Leeds General Infirmary in an attempt to stem the controversy over a picture that showed a sick child who had been forced to sleep on the floor because of a lack of beds.

Mr Hancock's visit came amid growing anger over the Conservative response to the photograph. He was sent after Boris Johnson refused to look at the photograph during an interview, a decision that led to fury on social media and criticism of the Tory party.

Soon after Mr Hancock arrived at the hospital, a flurry of reports suggested that a Labour protestor had attacked one of his aides outside.

General election: On the campaign trail Show all 114 1 /114 General election: On the campaign trail General election: On the campaign trail Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire AFP via Getty General election: On the campaign trail A sculpture of an owl is bedecked with an EU beret as Liberal Democrat leader Jo Swinson gestures during an interview at a general election campaign event in Bath AFP via Getty General election: On the campaign trail Boris Johnson (C) talks during a question and answer session on a general election campaign visit to Ferguson's Transport in the town of Washington, west of Sunderland AFP/Getty General election: On the campaign trail Boris Johnson tries to save a shot during a warm up before a girls football match while on the campaign trail in Cheadle Hulme, northwest England POOL/AFP via Getty General election: On the campaign trail Jeremy Corbyn makes cup of coffee as he campaigns in Barry, south Wales AFP General election: On the campaign trail Nicola Sturgeon poses as she launches the SNP campaign bus tour, at Queensferry Crossing in Edinburgh, Scotland AFP via Getty General election: On the campaign trail Boris Johnson reacts as he changes a wheel of a Formula One car during a Conservative Party general election campaign visit to Red Bull Racing in Milton Keynes POOL/AFP via Getty General election: On the campaign trail Britain's Prime Minister Boris Johnson visits a Christmas market in Salisbury REUTERS General election: On the campaign trail Liberal Democrat Leader Jo Swinson on the election campaign bus on route to Chelmsford PA General election: On the campaign trail Labour leader Jeremy Corbyn talking to a university worker outside Birkbeck/SOAS University of London, at the announcement of his parties of the plan for the extension of workers' rights PA General election: On the campaign trail Nicola Sturgeon plays a game with string during a visit to Perth and District YMCA Getty Images General election: On the campaign trail Brexit Party leader Nigel Farage picks up a copy of The Brexiteer during a visit to JPI Printers in Dinnington PA General election: On the campaign trail Boris Johnson, centre, talks to veteran James Gammer as he visits a veterans centre AP General election: On the campaign trail SNP supporters meet First Minister Nicola Sturgeon following her address during a St Andrews day election speech Getty General election: On the campaign trail Jeremy Corbyn has a photo taken outside Birkbeck/SOAS University PA General election: On the campaign trail Liberal Democrat leader Jo Swinson during a visit to the Cardiff United Synagogue PA General election: On the campaign trail Brexit Party leader Nigel Farage reacts as he attends an election debate ITV/Reuters General election: On the campaign trail Jeremy Corbyn wears a jacked displaying Labour's slogan 'For the many, not the few' EPA General election: On the campaign trail Prime Minister Boris Johnson on The Andrew Marr Show Getty General election: On the campaign trail Nicola Sturgeon plays with local children during a visit to the Jelly Tots & Cookies Play Cafe in Uddingston, South Lanarkshire PA General election: On the campaign trail Opposition Labour Party leader Jeremy Corbyn eats some chips in Whitby, northern England AFP via Getty General election: On the campaign trail Boris Johnson and Conservative MP George Eustice, left, tour 'Rodda's Clotted Cream' whilst campaigning in Cornwall Getty General election: On the campaign trail Jo Swinson during a visit to Dunkertons Cider Company, an organic and plastic free brewery in Cheltenham PA General election: On the campaign trail Jeremy Corbyn holds up unreacted documents with NHS staff. 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The BBC's political editor, Laura Kuenssberg, said that activists had rushed to the hospital and that it "turned nasty when they arrived – one of them punched Hancock's advisor". ITV's political editor Robert Peston suggested that the advisor had been "whacked", and other political reports posted the claims.

None of those tweets gave the name or details of who they had heard about the attack from. While Ms Kuenssberg and ITV's Paul Brand explicitly said the reports had come from the Conservatives, they gave no more information, and others reported the claim as if it was fact.

Those claims were then carried across much of the press, with push notifications and breaking news alerts sent out to readers.

As other news organisations scrambled to verify the original claim, it started to become clear that there had been no such attack. The police said that it had received no reports of any such attack.

"We are aware of information circulating on social media in relation to an alleged incident involving election campaigners at Leeds General Infirmary this afternoon," West Yorkshire Police said in a statement.

"We are currently unaware of any reports to West Yorkshire Police of this nature but are seeking to verify."

Nobody who was involved is understood to have filed a report with the police, and the incident only came to their attention through social media.

Shortly after, video emerged of the incident. It showed that Mr Hancock's aide had not actually been punched – and that instead he had walked into the hand of a man who was not facing him and had been pointing to his side.

Many of those who shared the original claim posted that footage with some indication that their earlier claims were wrong.

Robert Peston, who had shared the original claim, said he had been told about it by "senior Tories". He admitted that there had been no punch.