On the eve of 4/20, cannabis smokers' unofficial holiday, Barack Obama has appeared on CNN's special report WEED3 backing decriminalisation of marijuana, saying that he favours a "public health model" over an "incarceration model".

The president stopped short of endorsing the legalisation of the drug, but did signal support for the medical marijuana bill backed by Rand Paul.

Interviewed by CNN's chief medical correspondent and vocal legalisation advocate Dr Sanjay Gupta, Obama said: "You know, I think I’d have to take a look at the details.

"I’m on record as saying that not only do I think carefully prescribed medical use of marijuana may in fact be appropriate and we should follow the science as opposed to ideology on this issue, but I’m also on record as saying that the more we treat some of these issues related to drug abuse from a public health model and not just from an incarceration model, the better off we’re going to be." Many journalists have tried to get Obama to talk openly about marijuana and this is about his most positive statement yet, having previously admitting to smoking it in his youth and saying that he views it as no "more dangerous than alcohol".

Legalisation has given a massive financial boost to Colorado, where crime has not been affected by the law changes, while Oregan, Washington state and the District of Columbia also managed to approve recreational use of the drug without spontaneously bursting into flames.

Despite this, and the fact weed has been found by scientists to be 114 less deadly than alcohol, earlier in the week a California judge decline to remove it from the federal list of the most dangerous drugs.

Unexpected successful people who have admitted to smoking cannabis Show all 14 1 /14 Unexpected successful people who have admitted to smoking cannabis Unexpected successful people who have admitted to smoking cannabis Barack Obama "As has been well documented, I smoked pot as a kid, and I view it as a bad habit and a vice, not very different from the cigarettes that I smoked as a young person up through a big chunk of my adult life. I don’t think it is more dangerous than alcohol.” Getty Unexpected successful people who have admitted to smoking cannabis Bill Maher "Look, I have never made a secret of the fact that I have tried marijuana... About 50,000 times." Getty Images Unexpected successful people who have admitted to smoking cannabis Boris Johnson "It was jolly nice. But apparently it is very different these days. Much stronger. I've become very illiberal about it. I don't want my kids to take drugs." AP Unexpected successful people who have admitted to smoking cannabis Bill Clinton "I experimented with marijuana a time or two." Reuters Unexpected successful people who have admitted to smoking cannabis Jon Stewart “Do you know how many movies I wrote when I was high?” Comedy Central Unexpected successful people who have admitted to smoking cannabis Harriet Harman "I did, when I was at university, smoke cannabis once or twice." But she quickly added she had not taken the drug since then. "I have indulged in the odd glass of wine but not cannabis." PA Unexpected successful people who have admitted to smoking cannabis Martha Stewart “Of course I know how to role a joint.” Getty Images Unexpected successful people who have admitted to smoking cannabis Bill Gates In Stephen Manes’ biography about the Microsoft founder, he writes: “As for drugs – well, Gates was certainly not unusual there. Marijuana was the pharmaceutical of choice…” Chip Somodevilla/Getty Images Unexpected successful people who have admitted to smoking cannabis Oprah Winfrey Asked by Andy Cohen when the last time she’d smoked cannabis was, she answered: “Uh … 1982.” “Let's hang out after the show,” Cohen joked. “Okay,” Winfrey said, laughing. “I hear it's gotten better.” Getty Images Unexpected successful people who have admitted to smoking cannabis George W. Bush "I wouldn't answer the marijuana questions. You know why? Because I don't want some little kid doing what I tried." Getty Unexpected successful people who have admitted to smoking cannabis Sarah Palin "I can't claim a Bill Clinton and say that I never inhaled.” AP Unexpected successful people who have admitted to smoking cannabis David Letterman “I went through one period when I smoked a surprising, a really breath-taking, amount of grass almost every night.” Getty Images Unexpected successful people who have admitted to smoking cannabis Morgan Freeman "Never give up the ganja." Getty Images Unexpected successful people who have admitted to smoking cannabis Steve Jobs “The best way I would describe the effect of the marijuana and the hashish is that it would make me relaxed and creative.”

Obama suggested that a policy similar to those for tobacco and car seatbelts could work for marijuana.

"You know, we save tens of thousands, hundreds of thousands of lives every single year," he added to Gupta. "We didn’t throw anybody in jail; we just made sure that they were well-informed and if somebody has an addiction, we made sure that we made it easy for them to get help.

"And I think we need to re-emphasize that approach [for marijuana], because we don’t want to encourage our kids to engage in drug use, but there are going to be more effective ways than, too often, the approach we’re taking today."