Maja Petersen, 38, a prostitute, could not wait a moment longer for her fix. She had made her way to Copenhagen's drug consumption room, hoping to inject there, away from public view and within sight of its nurses. But the room – a place where addicts can use class A drugs free of fear of prosecution – doesn't open its doors to the city's 8,000 addicts until 8.30am.

At 8am last Wednesday, she sat down on the cobbled street outside and plunged a syringe into her arm, flushing cocaine into her bloodstream. Speaking shortly afterwards, with tears welling in her eyes, she estimated that she would inject herself another 20 times that day with cocaine, methadone, or a mixture of the two – her usual routine. "With cocaine you want more and more and more. If you have it, you take it," she said. "I hate life. I don't have a life any more. But I have never taken too much. I have never tried to die."

Not wanting to die is the reason why Petersen, like the 1,000 regulars at what the Danes call the "fixing room", make their way to this small health centre in a square that it has made its own, walled off from view, in Copenhagen's Vesterbro area – the city's former meat-packing district.

Even the most addled addict is unlikely to die here under the watch of medics and social workers. It is why, back in Britain, Brighton's public health leaders will meet this summer to "give serious consideration" to establishing a similar facility in the city, where 110 people died drug-related deaths between 2009 and 2012.

Maja Petersen, right, outside the drug consumption room. She says she uses the facility to stay alive. Nurses have dealt with 36 overdoses there, with no fatalities. Photograph: Mikkel Østergaard/Panos for the Observer

Copenhagen's drug consumption room is small, but it is the latest incarnation of the idea of a safe haven for addicts and those behind it have learned lessons from about 90 others around the world. Last month's revelation in the Observer that there is a movement championing a similar facility on the south coast of England drew predictable fire from the rightwing commentariat. If Brighton does go ahead, it may wish to learn from Denmark.

In Copenhagen's fixing room, eight people at a time, and another four in a van parked up in the courtyard, inject, in the knowledge that they are being watched over by nurses and are taking their drugs in a clean environment using sterile needles, a dose of saline solution, a cotton bud and a pump, all provided by staff.

A large anatomical drawing of a man shows users the location of their main veins and arteries, and there is even a machine addicts can use that illuminates a healthy vein to spike. The atmosphere is tense; drug-takers can be mercurial and outbreaks of violence have been known. But, incongruously, it has the atmosphere of a library, as the addicts crouch in their booths, complete with small desk lamps, offering few words beyond the odd call for hush to those who make a noise. Those who inject cocaine – the favoured drug in this area – become extremely sensitive to noise while high.

It is not a pleasant place, but it is very popular. There have been more than 36,000 injections in the room since it opened in October, with the addicts getting through as many as 350 syringes a day. There have been an additional 13,000 injections in the van, about 40 a day. Most users, about 75%, are male and two thirds are aged 31-50.

Crucially, while nurses in the room have dealt with 36 overdoses in the last seven months, not one has been fatal – as is the pattern in the other drug-consumption rooms around the world. Dealing in drugs is forbidden and the police carefully monitor those hovering outside. They will enter the room and its courtyard if necessary, but they don't come in for "the sake of it", said Superintendent Henrik Orye.

The lives of addicts are without doubt being saved. All the evidence, here and internationally, suggests so. But there is much more to it than that, proponents say. When Petersen and the others have finished with their needles, they put them in a sharps bin. Up to 10,000 syringes used to be picked up off the streets of Vesterbro every week before the room opened. Everyone in the area appears able to tell a tale of a child they know who has been spiked, although none of them appears to have been infected. Since the launch of the room, the quantity of drug paraphernalia collected from gutters, playgrounds, stairwells and doorways in the area has halved.

Vesterbro also appears to be a place where the desperate are seemingly becoming a little less desperate. Year on year, burglaries in the wider area are down by about 3%, theft from vehicles and violence down about 5%, and possession of weapons also down. "From the police perspective, I can see the benefits," said Orye. "It feels calmer."

Critics say that such rooms make it easier for drug users to abuse themselves and send the wrong message. Only five people using Copenhagen's room have been put on treatment since October.

Petersen, like many others using the room or floating around the courtyard outside, said that she does not want and would never seek treatment. But every day that she comes here to inject she meets health professionals, social workers and people offering treatment in case she suddenly want to rise from rock bottom, say the room's staff. Petersen might change her mind one day, said Nanna Gotfredsen, a lawyer who campaigned for the room.

Michael Olsen, a local resident who was a key figure in persuading authorities to accept the idea of a consumption room, said that he felt moved to champion the cause when he found addicts taking drugs in his bins, and women urinating in a phone box because all the toilets in the area had been sealed to stop addicts injecting there. "There is no country that has solved this problem, so surely, until we solve it, we can meet their basic needs – access to food, a toilet, medical help and a safe place to take their drugs," he said. Ivan Christensen – who runs a nearby hostel for the homeless which, in partnership with the Copenhagen town hall, manages the consumption room – said that ultimately it is about harm reduction rather than treatment. "We don't do this to get people out [of drugs]," he said. "We are happy when we do, but at first it is helping people in the situation they are in.

"We just intervene when they ask for help because we do not demand that they change, or push them to change. The philosophy is that we can't change people, people can change themselves and we can be there when they want to change."

Frank Nealson, 42, who has been using cocaine and heroin, among other drugs, for 27 years, is surprised that anyone could believe consumption rooms encourage use. "The reasons I use drugs, and where and how I use drugs, are two separate things. This place makes sure I don't do it in the street, don't pick up diseases from dirty needles, and that is it."

There is a plan to open a second facility, with a smoking room, further up the road. It will be called The Cloud. But the local authority is struggling to win acceptance from all residents. The high school, which is across the road from the current consumption room, is worried for its students, said Michael Knudsen, the caretaker. "We can't live with it so close."

Martin Petersen, 43, who lives on the road where the second room is planned, said that he believed the consumption room had reduced the number of addicts he saw injecting on the street by half. Pointing to the blood splatter on the archway above the door to his flat, caused by an addict injecting in a neck artery, he said: "That used to be normal."

But Petersen said that he was also concerned about the location. "It is a good idea, but there is a lot you need to get right." A warning for Brighton then. But experience of the Copenhagen room also offers a great deal of encouragement.