DRUGS FEATURE: Methadone is a synthetic narcotic that has been used to treat heroin addiction for 30 years.

It mimics the effect heroin has on receptors in the brain, reducing the cravings addicts experience when coming off the drug.

The green liquid, which looks like cough mixture, produces feelings of sedation, without the euphoric rush associated with heroin.

Methadone must be taken in the presence of a pharmacist.

Initially, the dosage is slowly increased to allow the patient to build up tolerance to the drug.

It is then slowly decreased until, hopefully, they are cured of their habit.

An assessment clinic is held at the Swindon and Wiltshire Alcohol and Drugs Service (SWADS) in Milton Road on Mondays between 9.30am and 11.30am. SWADS can be contacted on 01793 695405. Drug workers stress that methadone is just one option for treatment that is appropriate only in certain cases.