Most people alarmingly underestimate the health risks of smoking cannabis, the National Lung Foundation has warned.
Almost 90 per cent of people think a tobacco cigarette carries a greater risk than a cannabis joint – but the risk of lung cancer is actually 20 times higher with cannabis.
The British Lung Foundation (BLF) carried out a survey of 1,000 adults, and a third wrongly believed cannabis did not harm health.
The BLF said the lack of awareness was “alarming”, and issued a report warning people about the dangers.
The BLF report warned that smoking one cannabis cigarette every day for a year increases the chances of developing lung cancer by a similar amount as smoking 20 tobacco cigarettes each day for one year.
Someone smoking a cannabis cigarette inhales four times as much tar as from a tobacco cigarette, and five times as much carbon monoxide.
BLF chief executive, Dame Helena Shovelton, said: “It is alarming that, while new research continues to reveal the multiple health consequences of smoking cannabis, there is still a dangerous lack of public awareness of quite how harmful this drug can be.
“This is not a niche problem – cannabis is one of the most widely-used recreational drugs in the UK, with almost a third of the population having tried it.
“We therefore need a serious public health campaign – of the kind that has helped raise awareness of the dangers of eating fatty foods or smoking tobacco – to finally dispel the myth that smoking cannabis is somehow a safe pastime.”