A senior health advisor is facing criticism for his links to a company involved in a million pound drug trial.

Professor John Strang, an architect of drugs policy for more than a decade, is chief clinical investigator in a publicly funded heroin-antidote trial on thousands of prisoners.

Questions over Professor Strang's links comes just months after he was criticised for failing to disclose ties to drug companies when applying for a government project.

The latest case has caused outrage among campaigners who say drug addiction policies have for too long been open to abuse from vested interests. The issue will be discussed by the Inter Ministerial Group on Drugs this week, The Independent has learnt.

Professor Strang has confirmed receipt of research grants, consultancy payments and travel expenses from several pharmaceutical companies who make medicines to treat addictions including Martindale Pharma and Cardinal Health.

Martindale, owned by Cardinal Health until May 2010, was the manufacturer chosen by the researchers in 2009 to supply pre-filled syringes of the drug Naloxone being used in the pilot study which could eventually involve 56,000 prisoners in England. The study, called N-ALIVE, hopes to reduce overdose deaths in the first month after release from prison.

The relationship between Professor Strang, director of the National Addiction Centre at King’s College London, with Martindale Pharma has publicly emerged - three years after the £1m grant trial was approved by the Indian Council of Medical Research.

Martindale, owned by Cardinal Health until May 2010, was the manufacturer chosen by the researchers in 2009 to supply pre-filled syringes of the drug Naloxone being used in the pilot study which could eventually involve 56,000 prisoners in England. The study, called N-ALIVE, hopes to reduce overdose deaths in the first month after release from prison.

He did not formally declare any conflicts of interest to the ICMR during the application process - which the ICMR says complies with current rules.

Professor Parmar, senior ICMR board member, director of the ICMR clinical trials unit and head of N-ALIVE, said: “Professor Strang told me about his links to drug companies but it was not material to our decision to use Martindale so I decided there was no need to further dissect these links… We followed normal processes but I agree that you have raised a fair point that warrants broader discussion.” (must keep)

No-one else was involved in this decision, which is again within current rules. Researchers must formally declare interests only when submitting a paper for peer review – after the study is complete.

The Ministry of Justice and Department of Health approved the prison-study but claim it was not their role to check for conflicts of interest. A letter was sent to prisoner governors and NHS bosses about N-ALIVE from government officials and the three researchers written on MoJ and DH headed notepaper. Critics say the government ought to have known about Professor Strang’s link with the drug company which should have been declared in this letter.

The ICMR N-ALIVE webpage has recently added some limited declarations of interest to Professor Strang’s profile but no drug companies are mentioned by name. The change was made as health officials were alerted to the “potential embarrassment” by a drug policy campaigner and after a freedom of information request by Kathy Gyngell, research fellow at Centre for Policy Studies.

MPs and drug experts last night called for urgent action to ensure external government advisors and arms length bodies, often instrumental in shaping government policies, are forced to declare all potential conflicts of interests.

It is the second time in a year that Professor Strang’s pharmaceutical links have been questioned. In July, The Independent revealed how Professor Strang had failed to disclose links with drug companies that sell tranquilisers such as Valium before conducting a DH review into the same drugs. His report is guiding government policy in this area.

Professor Strang’s presentation advocating Naloxone is on the United Nations Office of Drug Control website. His declaration of interests includes several drug companies but there is no mention of Naloxone manufacturer Martindale.

Jim Dobbin, chair of the All Party Group on Involuntary Tranquilliser Addiction, said: “All advisors or researchers who may influence government policy must declare any links with organisations or companies that could benefit from Government policy, so that there is complete transparency. The government must urgently review what information it explicitly asks influential external advisors like Professor Strang so that every link with every company is known.”

Eric Ollerenshaw, Tory MP who campaigns for better addiction services said: “I am not a medical expert, so I need to know that so-called independent advisors being relied upon to make drug policies are actually independent of drug companies.”

The £984,000 grant for the N-ALIVE pilot study involves 5,600 prisoners. The main study, which will cost at least £5m, will test whether giving known heroin users pre-filled syringes of the antidote upon release reduces deaths in the first four weeks by 28 per cent. Success will depend on the overdose taking place in the presence of others who are able, and willing, to inject the antidote within 20-30 minutes.

But drug experts are still divided about safety and the principle of take-home Naloxone to treat heroin overdoses.

It is routinely carried in ambulances and Professor Strang, a staunch supporter for more than 10 years, claims the drug could save hundreds of lives if routinely carried by heroin-users. It has been rolled-out in Scotland, despite a lack of robust clinical evidence; there are ongoing concerns about potential side effects especially when administered without medical supervision.

Critics argue that limited resources should be targeted at longer-term solutions, including helping addicts to detox in prison and providing addiction support upon release.

Dr Alex Wodak, former president of the International Harm Reduction Association, said the study would determine whether Naloxone was safe and cost effective. “Naloxone is very interesting but the evidence is still weak… Whether money is better spent on research or on proven interventions is always a real dilemma - in my view we should do both.”

Kathy Gyngell, a vocal critic of drug-focused addiction policy, said: “That the ICMR can act as judge and jury over declaration of interests is not just slack; it is unacceptable. The ICMR will have little credibility and less respect if it does not now request a full declaration of Professor Strang's relationship with the Pharmaceutical companies he done research for and whose products he advocates… Given that Naloxone is a highly controversial intervention… he should be subject to immediate and independent investigation.”