Tony Blair's hint that the downgrading of cannabis may be reversed means drugs is firmly back on the political agenda at the start of the new term. In his new book, Griffith Edwards, founder of the National Addiction Centre, offers some radical solutions.
Cannabis, the drug of choice for students and regarded by millions of otherwise law-abiding people as a harmless high, is the subject of renewed debate about its effect.
It was downgraded last year to Class C, the same as steroids. This made most cases of cannabis possession a non-arrestable offence.
But in March, the Home Office ordered a review after fresh research suggested the drug could be more harmful than previously thought.
And on the final day of the election campaign, the prime minister hinted at a U-turn. "We have asked for advice on it," he said. "What we did was perfectly sensible but I think it sent out the wrong message."
A study by New Zealand scientists suggested smoking cannabis virtually doubled the risk of developing mental illnesses such as schizophrenia.
Mr Edwards, an expert in alcohol and drug addiction and founder of the National Addiction Centre, says he may have wrongly assessed cannabis himself.
"Thirty or 40 years ago I was writing that cannabis was a drug without harm and dependency but I've had to eat my hat now," he says. "That doesn't mean it's a growing evil but, rather like cigarettes, we need controls in place and a serious message.
"The evidence says there's an increasing risk of schizophrenia and mental ill-health, and there are implications for traffic safety," he says, noting cases where drivers have been using the drug. "That needs to be considered by people making a decision about its classification."
But next to more harmful drugs like crack cocaine and heroin, the classification of cannabis is a tokenistic argument, he says. These drugs are predominantly a problem for the poor and so tackling poverty should be at the heart of drugs policy.
"If you got rid of deprivation tomorrow you would get rid of the major part of drugs problem. You need to also address the economic deprivation in countries like Colombia, Afghanistan and Thailand as well.
Afghans grow opium to feed their families, says Mr Edwards
"It's a social responsibility that if you do something about drugs, you do something about deprivation. We've been thinking too much about the individual drug taker but not the conditions that cause it."
More money for education, housing and amenities in poor areas is the answer, he says. But people are afraid of making the connection between drugs and poverty because it's seen as blaming or excusing the poor.
Tobacco offers some proof, he says. Smoking has become a drug of the privileged to a drug for the poor because it's easier to give up if you're middle-class.
Mr Edwards, 76, makes this argument in his new book, Matters of Substance, which he says does not tell people what to think but gives them the "tool-kit" to consider the options. The book looks at drug control in the context of times when drugs like cocaine were legal.
"We've had historical amnesia. Cocaine epidemics in the 1920s across America, Europe, and India caused considerable worry. Cocaine wrecked people and the borderlines between medical and recreational use was crossed."
Legalisation may save police time and stop criminalising people unfairly, but it would also increase supply and consumption, he argues. And society has before turned against cocaine, heroin and amphetamines when they were legal because it saw the damage they caused.
As well as tackling poverty, Mr Edwards says it is also necessary to do more about alcohol abuse and reduce the penalties for all drugs offences, because they criminalise vulnerable sections of the community.
"Sensible small laws such as drunk-driving and smoking in public places, can work but criminal laws can damage communities."
And the media has a key part to play by presenting information accurately.
"Rhetoric is a dangerous drug in its own right," he says.