Former Prime Minister Helen Clark says cannabis won't make your teeth fall out or turn your hair green - and criminalising it is an injustice to thousands of people every year. And she says it's not as bad for your health as legal substances tobacco or alcohol, a claim backed up by an expert panel's work that was published yesterday. Her comments come on the back of a new poll showing a tight race for the September referendum on legalising cannabis for recreational use, with 48 per cent support in favour and 43 per cent opposed. (See also: Legal cannabis has potential to reduce harm, but many unknowns: PM's chief science adviser)