Drug addicts are to be prescribed heroin on the NHS in a controversial plan to cut crime and get users off drugs.

Addicts would be allowed to inject themselves under supervision as part of a scheme costing £12,000 to £15,000 a year for every user.

The scheme is expected to be introduced in Brighton and Hove early next year, possibly February, in a bid to cut some of the dozens of drug-related deaths in the city each year.

Brighton and Hove was named the drug death capital of the UK in October.

Anti-drug campaigners have criticised the trial and said it would not help people to get off drugs.

The trial is being funded by the Home Office and run by the National Treatment Agency and Action On Addiction.

Heroin addicts will be given the drug with which to inject themselves in supervised surroundings, with a specially trained nurse in attendance.

They will receive two injections a day of diamorphine, pharmaceutical heroin, seven days a week and be given methadone to take home in the evenings.

A controversial trial has already been launched in London at the Maudsley Hospital and in Darlington. Addicts in Brighton and Hove will be chosen for the project by researchers from the Maudsley. Researchers will compare the progress of ten addicts given the drug to inject and ten who will be given liquid methadone.

Chris Hughes, substance misuse services manager at the Sussex Partnership NHS Trust, will be running the scheme in the city.

He said the study would involve 150 addicts across the country and 30 would come from Brighton and Hove.

The location of the scheme has not been announced.

Mr Hughes said the heroin would not leave the scheme's base.

He said: "We will be looking at people who have had difficulty benefiting from the mainstream treatments.

"We will be looking at dealing with people who don't respond well to heroin substitutes and being in hospital.

"A lot of people won't come forward for methadone treatment. If this trial is successful it will have all-round benefits for everyone.

"They will look to see the outcomes afterwards and monitor health, reduction in drug use and reduction in crime.

"At the end of the trial we review how people have managed in treatment and make decisions about how we go from there.

"If it is successful then this will be a reason to continue it."

The dose of diamorphine given to each addict would be worked out in the first couple of weeks of the scheme and remain constant throughout, unless the user requested its reduction.

Mr Hughes said: "The idea is to get them stable and keep them stable throughout the trial."

He said all participants would be tested regularly and if any were found to be topping up with "street" heroin, a review of their treatment would be carried out.

Critics have argued the city's high-quality support services attract addicts to the city. There are believed to be about 2,300 heroin addicts living in Brighton and Hove.

Peter Stoker, director of National Drug Prevention Alliance, said: "We're against the idea. It is perpetuating dependency.

"Abstinence should be their goal, not continuance. There needs to be a plan on how to give up not how to keep on using.

"We need to bear in mind that many users have people who are affected by their addiction."

Recovering heroin addict Rick Cook runs a service user group in Brighton.

He said he supported the trial but was concerned what would happen at the end of the trial.

Mr Cook said: "The downside would be the aftercare. Will people be supported after the trial ends? I have been assured they will be supported but it is a concern the trial would just stop."

Justin Grantham, a manager at Brighton and Hove's Crime Reduction Partnership, welcomed the trial but warned it would be controversial.

He said: "For every £100 an addict spends on drugs a week there is £300 of criminal activity a week, about £150,000 a year.

"I'm 100 per cent behind the scheme."

He said it would help cut drug deaths in the city because the heroin would not be contaminated and clean needles would be used in a supervised environment.