This is a pivotal moment on both sides of the Atlantic for the so-called war on drugs – a senseless battle that has been waged across the world since the 1970s.

As the UK home affairs committee's groundbreaking reportDrugs: Breaking the Cycle is launched, two US states have moved to decriminalise marijuana.

Drugs: Breaking the Cycle makes uncomfortable reading. The committee describes some of the unintended consequences of international prohibitionism ‒ including "massive harm and deaths around the world". Committee members saw for themselves during a visit to Colombia "the effect of the drugs trade on producer and transit countries ‒ the lives lost, the destruction of the environment and the significant damage caused to governance structures by corruption and conflicts."

Meanwhile, last month, Colorado and Washington voted to legalise cannabis, putting them on a collision course with the federal government, whose laws remain unchanged and whose enforcement policies look set to continue unabated. But even at federal level, progress can be made. President Bush took drugs and denied it. President Clinton took drugs and didn't inhale. President Obama has admitted taking both soft and hard drugs in his youth, and has moved on. This progress reflects a development in society, a growing-up and an acknowledgement that the D-word ‒ drugs ‒ is no longer an unbreakable taboo.

The key to reform is global citizens; ordinary people who alone have the power to move the agenda of change forward.

This is why the Beckley Foundation, which I founded 15 years ago to help reform global drug policy so it should be based on health, harm reduction, cost-effectiveness and human rights, has just launched the new global campaign website in association with the Global Commission on Drug Policy, Virgin Unite, Avaaz and Sundog Pictures. The site aims to garner over a million signatures for a petition to end the war on drugs, which will be presented to Ban Ki-moon, the UN secretary general.

The site features the film Breaking the Taboo, narrated by Morgan Freeman and directed by my son, Cosmo Feilding Mellen, which chronicles the failures of the war on drugs' prohibitionist approach, and considers alternative solutions. The film and the website were launched at Google's headquarters in London last Wednesday, and at their New York headquarters on Thursday ‒ which is why I came here last week to join former President Fernando Cardoso of Brazil, Sir Richard Branson, Natalie Imbruglia, and others for the launch. On Friday, the film went on global release on a dedicated YouTube channel, which has already gathered around 300,000 visitors.

Two Latin American leaders ‒ President Santos of Colombia and President Pérez of Guatemala ‒ have signed the Beckley Public Letter (the Mission Statement of the new global campaign), which declares the war on drugs a failure and calls for a new approach. Other signatories include seven former presidents (among them Jimmy Carter); 12 Nobel prizewinners; and a Who's Who of internationally-respected figures from the worlds of politics and diplomacy, academia, business and the arts.

There is more than a coincidence in timing between the releases of Breaking the Cycle and Breaking the Taboo. Breaking the Cycle, compiled after an extensive inquiry which heard evidence from all sides of the debate, is a balanced distillation of policy findings and recommendations. But, unfortunately, political leaders are loth to act unless there is a clamour of public opinion behind them. Breaking the Taboo aims to stimulate public awareness and so to embolden politicians to face the facts and take action.

The home affairs committee's report is vitally important, but unless political leaders implement its recommendations, the inquiry will have been wasted. The evidence in favour of reform is overwhelming, and it will not go away. Let us break the taboo on debate and reform. The time for action is now.