The medical profession has reached a consensus. The front page of last week's BMJ reads "Drug users and HIV: Treat don't punish". Within its pages is a an analysis piece entitled "Why Russia must legalise methadone" and a report on the Vienna declaration, which calls for the incorporation of scientific evidence into drug policy.

Meanwhile, the Lancet has a series of papers highlighting that while there have been large gains in fighting the HIV epidemic in the general population, the socially marginalised such as people who use drugs and who often enter prison systems, continue to be denied access to treatments, particularly opioid substitution therapy that both saves lives and prevents HIV transmission to others. The Lancet's editor, Dr Richard Horton, says: "Complacency about the HIV/Aids epidemic now would be a terrible mistake."

The evidence for the benefit of treatments such as methadone is overwhelming. At a time when the UK should be leading the way in ensuring such benefits are available everywhere I am left wondering why the UK National Treatment Agency for Substance Abuse is instead pandering to politics by raising the possibility of returning to the outdated and discredited policy of time-limited methadone prescribing.

As a doctor I use methadone and buprenorphine with many patients alongside a variety of psychosocial and other healthcare interventions. Prescribing can last for one week or it can last for 30 years – it is and should be completely patient-driven and dependent on them as individuals. An arbitrary time frame imposed on any patient's medication regime is unacceptable and I for one will not accept such political interference. It is essential that this new government's drug policy is based on sound evidence and we the clinicians must strongly resist a potentially lethal change to policy.

Most sensible clinicians see abstinence as one end of a spectrum and see no conflict whatsoever with substitute prescribing. In my experience most people working in the field want the best for their patients. I am deeply offended by language such as "people indefinitely parked on methadone", "routinely writing off full potential" etc. If any of my patients wants to try and come off all drugs – they have my full support.

Recently a group of doctors launched International Doctors for Healthy Drug Policies after becoming increasingly aware over the past few years of the wide divide between what we know works and the drug policy made by politicians and their appointees – most who have no background in practice and never meet nor work with people who use drugs.

Reliable and persistent research shows that substitute prescribing treatment substantially reduces deaths, crime, HIV infection and drug use while also assisting social functioning such as improved education, training, parenting and employment. Methadone treatment has been endorsed by UN agencies: the United Nations Office on Drugs and Crime , the World Health Organisation and UNAIDS, as well as Nice and the Department of Health in the UK. The WHO has also included methadone treatment in its "essential medicines" list and 70 countries in the world now provide methadone or buprenorphine treatment to an estimated 1 million patients. It is up to us to ensure that this life-saving intervention is made available in countries such as Russia and the Ukraine where it could be saving literally millions of lives. Politicians in the UK must take up this global challenge instead of using people's fear of drugs and the use of false dawns in addressing these fears to gain a little extra popularity.