Police have been accused of groping and manhandling female anti-fracking protesters, including pulling their clothes to reveal their breasts.

A team of academics, who have been studying anti-fracking demonstrations for three years, alleged that police had treated female protesters more physically than male protesters.

“These tactics have been understood by protesters as an exercise of power and have left women feeling violated and frightened,” they said.

In a report, the academics said protesters had described how police had regularly used violence and aggression to intimidate them during demonstrations.

Disabled and older protesters had also been subjected to violent policing, they said. They recorded testimonies from protesters who said police officers had shoved, pushed and dragged them.

“In some cases … this type of violence was said to take place on a daily basis and became a defining feature of the experience of protest,” they said.

“Some of these violent incidents have led to protesters reporting physical injuries, including severe bruising, broken bones and chronic pain.”

Long-running protests have helped to force the government to halt fracking in England unless compelling new scientific evidence proved the practice could be safe.

Researchers from Liverpool John Moores University, the University of York and the School of Advanced Study at the University of London studied the policing of protests at seven fracking sites in England since 2016. They conducted in-depth interviews with 31 campaigners.

The academics reported that police treated female protesters differently. “Many protesters outline marked differences in how men and women are policed, albeit both violently, with women protesters reporting being physically moved, carried and manhandled using specific restraint techniques.

“Broadly conceived, these techniques involve a much closer form of bodily contact between women protesters and male police officers, which, according to the testimonies we have collected, includes the use of groping and tactics such as the pulling of clothing to reveal women’s breasts.”

The report quotes a 45-year-old female protester saying: “I’ve seen women have their tops, as they’ve been restrained or dragged, their tops are deliberately pulled up so that their breasts and bras are exposed … I’ve seen girls pulled by their hair, if they’ve got hair in ponytails and stuff like that.”

The report does not identify specific incidents. Dr Will Jackson, one of the academics, said the different treatment of women was a recurring theme of their research which was recorded as happening at more than one site.

He said the academics did not want to identify any of the protesters as they had been promised anonymity as a condition of being interviewed.

The academics concluded that police tactics at anti-fracking protests were disproportionate and undermined the right to protest, adding that the nature of the policing operations appeared incongruous to the peaceful character, and relatively small number, of protesters.

They suggested that “the use of violent police methods is not in response to violent behaviour by protesters or in response to acts of criminality”.

“In some instances, this reported violence has had an effect on the willingness and capacity of some protesters to engage in anti-fracking campaigns. This has serious consequences for rights to freedom of assembly and expression.”

They said the use of confrontational and violent policing tactics appeared to be particularly pronounced during intense and extended protests.

The report said that protesters who submitted official complaints to the police often found these were “dismissed without thorough investigation”, a claim rejected by the police as speculative.

The National Police Chiefs’ Council lead on shale, gas and oil exploration, DCC Terry Woods, said: “The police service always welcome feedback concerning policing operations and we will always consider carefully issues raised with us.

“However, I feel there has been a missed opportunity to make this a more meaningful piece of research by not consulting the police for their side of the story, and limiting the research to the opinions of a small number of people with what appears to be a similar point of view.

“Nevertheless, the police service will continue to work tirelessly to engage with all interested parties and to balance the rights of all those protesting.”