Nick Clegg is launching a campaign to persuade EU leaders to back global reform of drugs laws, warning that the current punitive approach has failed to curb the multibillion trade in illicit substances and has criminalised millions of young people.

Until now, European leaders have been all but silent on international drug policy reform <p>Nick Clegg</p>

Writing in The Independent, the former Deputy Prime Minister says: “We are, without doubt, losing the war on drugs.” Mr Clegg is to urge European leaders to make the case for a new global approach to drug abuse at a United Nations meeting next year. Many of them have switched tactics in recent years, tackling it as a health issue rather than a law and order problem.

Mr Clegg is being financially supported in his mission by Sir Richard Branson and the American billionaire George Soros, both passionate advocates of drugs reform.

The move marks Mr Clegg’s first campaign since stepping down as leader of the Liberal Democrats after their general election disaster.

The party, which has called for Britain to follow Portugal’s lead and decriminalise the use and possession of almost all drugs, clashed in the Coalition with the Tories, who are strongly opposed to reform.

Mr Clegg hopes a UN special session on global drugs policy will conclude that the time has come to break from a 50-year-old approach which treats “repression and punishment as the solution to the drug problem”.

Countries in Central and South America are pressing for reform but are being opposed by nations such as Egypt, Pakistan and Russia, which take an uncompromising attitude to drugs.

Mr Clegg writes: “There is much to play for, but a real risk that this opportunity for modernisation will be lost if the hardliners are allowed to assert their position unchallenged. Until now, European leaders have been all but silent on international drug policy reform.”

Arguing that the time has come to “reassert European leadership” on the issue, he takes a swipe at his former Coalition partners, saying: “I have seen for myself the tendency for governments to place drugs reform in the ‘too difficult’ category. The UN summit next year should serve as a catalyst for politicians across the EU to give this issue the focus it deserves.”

Sir Richard and Mr Soros are contributing towards Mr Clegg’s travel and office costs as he uses his contacts from his days in government to urge European leaders to back the case for reform. He is not being paid for the work.

Sir Richard, a member of the global commission on drugs policy, appeared jointly with Mr Clegg before the election to argue that drug possession should be treated primarily as a health issue.

Mr Soros has reportedly donated more than $200m (£130m) through his foundation to championing drug reform over the past 20 years. He told the Financial Times last year that the war on drugs had been a “$1trn failure”, adding: “For more than four decades, governments around the world have pumped huge sums into ineffective and repressive anti-drug efforts.”

Mr Clegg has established a not-for-profit company to pursue his political interests, which also include Europe and mental health. Funded by private donations, it pays for a small research team working from central London.

Last month Mr Clegg, who fought off a strong challenge from Labour in his Sheffield Hallam constituency, also joined the board of the Social Mobility Foundation.

The European approach

Portugal: Decriminalised all drugs in 2001 and numbers of deaths from overdoses are far below the EU. People with a small quantity of any illegal drug for personal use are referred to a panel comprising a doctor, social worker and lawyer. No criminal sanctions are applied.

Switzerland: Acted in the early 1990s when Platzspitz park in Zurich became known as “needle park” and HIV rates were among the highest in Europe. Patients are given injections of heroin under medical supervision as part of treatment for opiate dependency. Death rates, HIV levels and crime have fallen sharply.

Netherlands: Has effectively decriminalised the use of “soft” drugs, including cannabis, allowing the sale of small amounts through coffee shops. Possession remains illegal, but police and courts operate “a policy of tolerance” towards small amounts. Proportion of drug-related deaths believed to be Europe’s lowest.