The United Nations drug agency has been caught in an embarrassing row over drug policy after Sir Richard Branson, who is a member of the Global Commission on Drug Police, leaked an official document which appeared to back  decriminalising possession of drugs.

The document from the United Nations Office on Drugs and Crime (UNODC) said liberalisation of laws on controlled substances may need to be carried out world-wide.

But the significance of the two-page paper was immediately contested by UN chiefs in Vienna, who said it did not amount to official policy.

A few day earlier a report by the BBC said that the United Nations Office on Drugs and Crime (UNODC), the agency that has overseen the global drug war for 50 years, has been blocked from announcing its momentous new position – that all countries should decriminalise the possession of drugs for personal use. The UNODC was set to unveil the position on Sunday 18th October 2015, at the Harm Reduction International Conference in a short briefing paper which states that: “Member States should consider the implementation of measures to promote the right to health and to reduce prison – overcrowding, including by decriminalising drug use and possession for personal consumption”.

In a devastating critique of the harms caused by criminalisation, the UNODC states: “Protecting public health is a legitimate aim, but imposing criminal sanctions for drug use and possession for personal consumption is neither necessary nor proportionate. On the contrary, punishment aggravates the behavioural, health and social conditions of the affected people.”

However, it appears a member state got wind of the planned announcement, and has prevented or at least delayed the UNODC announcement of its position.

The document was drawn up by Dr Monica Beg, chief of the HIV/AIDs section of the UNODC in Vienna. It was prepared for an international harm reduction conference in Kuala Lumpur next month.

The UNODC oversees international drugs conventions and offers guidance on compliance.

Sources within the UNODC have told the BBC the document was never sanctioned by the organisation as policy. One senior figure within the agency described Dr Beg as “a middle-ranking official” who was offering a professional viewpoint.

The document, on headed agency notepaper, claims it “clarifies the position of UNODC to inform country responses to promote a health and human-rights approach to drug policy”.