A couple of thousand ravers were given the secret location for one of the annual highlights of the free party scene – the Easter bank holiday weekend Eggtek event.

The sun was shining and they arrived at a field on Ministry of Defence land in Lulworth, Dorset, in a state of high excitement about a weekend of dancing to techno music playing from a variety of different stages and sound systems in the heart of the countryside.

They knew that police were likely to arrive and intervene at some point because raves are illegal under the Criminal Justice and Public Order Act, which prohibits gatherings of more than 20 people on open land where the music played consists wholly or predominantly of “a succession of repetitive beats”. But they hoped to get a day or two of partying in before being moved on.

What happened next is disputed by police and ravers.

Police say the ravers threw plastic bottles and drink cans at them and that their response to being assailed by these “missiles” using officers with batons, riot shields, dogs and pepper spray was proportionate.

The partygoers, meanwhile, say they were shocked by the level of force used against them.

Footage has since emerged showing partygoers being dragged along the ground, bloodied and beaten by police. A week on from the annual rave the disputed accounts are continuing.

One man who appeared in the footage is said to have sustained a series of injuries including a fractured nose, wrist and toe along with cuts to his head. Another woman is pictured with a bleeding head wound. In another clip, a man being pushed along by riot officers is seen screaming in pain with his arms twisted behind his back.

One man, working with one of the sound-system crews, said: “Our crew was attacked by police with batons for just standing there. People assume we are a bunch of feral, unemployed, uneducated druggies but that couldn’t be further from the truth. People from all walks of life and all ethnic backgrounds come along to these events.”

He said that while some of the ravers were drinking alcohol and taking drugs, others were “stone cold sober: and the vibe was initially very peaceful”.

He continued: “A lot of thought and meticulous planning went into this event. We have tried in the past to make our parties legal and licensed but often police or the local council pull out at the last minute and then we lose a lot of money. So we make the parties free now and organise them ourselves.

“When we send out information about the location we ask people to bring their own food and water, litter bags to put their rubbish in and shovels to bury human waste so we can leave the site as we found it. We tell ravers to respect the location.”

A second raver who attended Eggtek said that initially the atmosphere was “beautiful”. “We walked past multiple coppers without any problem. Everyone was helping everyone else and the party was chilled until police sent in the riot squad,” he said.

One photograph from the period when police were at the site before officers in riot gear arrived shows a police vehicle stuck in a ditch. Ravers can be seen helping the police lift it out.

The images appear to show a confrontation between police and the crowd which began in a good-humoured manner but quickly became violence. Dorset police say the blame lies with the ravers who, they say, met officers with hostility and threw missiles.

Police have confirmed they have received complaints about use of force which they are reviewing.

A spokesperson for Dorset police said: “While responding to the incident involving a large number of people, our officers came under attack from missiles and faced a violent and hostile reception. Violence in our communities and against our officers will not be tolerated. This event caused significant disruption to local communities and we responded in order to bring it to a safe conclusion.

“The force has received complaints in relation to alleged use of force by officers during the incident. These will now be reviewed and, if appropriate, investigated in line with the usual force complaints procedure.”

One attender said: “A lot of the people who went along to this event for some peaceful partying have been left injured and traumatised. What matters now is that everything is investigated properly and not just swept under the carpet.”