A disabled man was dragged from his wheelchair by police as he protested against fracking outside a controversial site.
Shocking video shows disabled Nick Sheldrick being pulled out of the way of a 40-tonne lorry as police escorted it into the site.
Fellow campaigners say the man was unfairly treated, while officers argue they were keeping him safe.
The 36-year-old had been removed from his chair by police outside Cuadrilla's shale gas exploration site near Preston, Lancashire, where protests have been staged for weeks.
Police say he fell as officers moved him out of the carriageway, to stop him blocking a lorry they were escorting into the site.
Footage appears to show Mr Sheldrick rolling into the road in the middle of the convoy, between a police car and a truck.
He is pulled back from the path of the oncoming 40-tonne lorry, falls out of his chair and onto the ground.
The incident has provoked a furious online debate. Some praise the police for their patience, others condemn them for heavy-handedness.
Mr Sheldrick, from Blackpool, a former naval officer in the Merchant Navy, was paralysed from the waist down after an accident in 2012.
In April this year he claimed he was assaulted during a confrontation with a police officer at the same site.
Louise Robinson, who filmed the drama and posted her video on Facebook, accused police of being heavy-handed.
She can be heard shouting: "They're getting on Nick, they're getting on Nick.
"You just pushed a man who's paralysed on the floor. He is paralysed this guy, you've just knocked him out of his chair.
"No way, no way. You can't lift him."
She reads out the officer's badge numbers as she films them trying to lift him up.
A statement on Fylde Police's Facebook page said: "We are aware of comments and videos circulating on social media following an incident at the fracking site at Preston New Road early this afternoon involving a man in a wheelchair.
"As it is clear from the footage the man is appearing to be wheeling himself into the carriageway in between a police vehicle and directly into the path of a lorry that was being escorted to the site.
"Officers on scene have taken immediate action to keep the man safe and prevent him from being injured by moving him out of the carriageway and back towards the central reservation.
"During this intervention, he unfortunately fell backwards and came out of his wheel chair. His welfare was addressed at scene by officers and at this time no complaints have been made by the individual concerned.
"Our first priority is to keep campaigners and everyone else at the site safe and this will remain paramount."
Ms Robinson's video has divided opinion on social media.
Saul Nyland said: "They have a duty of care to protect people. They were protecting him from being run over by a 44ton."
Ryan Smallshaw said: "Get a job. Stop wasting police time."
But police have come under a barrage of abuse on their Facebook page.
Teresa Dixon condemned the police action, saying: "Disgusting treatment of a disabled man" while Kenneth Dodsworth said: "Heavy handed policing and totally unnecessary."
Steve Walmsley added: "Bang out of order."
Earlier this month, police announced they were beefing up security with 24-hour patrols at the site due to an increase in protests.
The government gave the green light for fracking in January after Lancashire County Council refused Cuadrilla's application to frack the site.
Drilling is expected to begin at the site by the end of August.