The government’s Tobacco and Vapes Bill, which would have made selling tobacco to anyone born after 1 January 2009 illegal, was not passed before the general election after the government ran out of time.
The policy was supported by Labour and Liberal Democrat MPs, although they were given a free vote so were not told to back the bill.
Sir Ed told the BBC he wanted a regulated market for cannabis, arguing that potent forms of the drug and smoking were both “very harmful to people’s health”.
Taking questions from the public during a BBC Radio 5 Live phone-in, the Lib Dem leader was asked if his support for the smoking ban impacted his stance on the legalisation of cannabis.
“Some people have said it is inconsistent and it is consistent,” he said.
He said the party’s policy was to bring in a regulated market for cannabis, so more potent and dangerous forms like skunk were not available.
“I’m banning skunk because that’s very, very harmful to people’s health. And cigarette smoking, everyone sees, it’s really clear it’s very, very harmful,” he said.
He added: “It was a real challenge for me, I’ll be honest with you, as a liberal.
“I don’t like banning things but the health arguments on things like skunk, on things like cigarette smoking are so overwhelming, that if you’re serious about the NHS and you’re serious about what happens to families when they lose their parents, you just need to act.”
Sir Ed explained his position partly related to his experience of losing both his parents to cancer.
Asked if he had ever smoked cannabis himself, he said he did “on a few occasions” at university but this was “very seldom”.
Pressed over whether the Lib Dems would consider legalising other drugs, such as magic mushrooms, he said the party wanted “evidence-based health policies”.
The Lib Dem manifesto, which sets out what the party would do if it was elected, pledges to take “‘skunk’ off the streets by introducing a legal, regulated market for cannabis”.
It says sales would be restricted to over-18s, from licensed retailers, with strict limits on potency.
The manifesto also promises to free up police time, reduce court backlogs and tackle prisons overcrowding by diverting people arrested for the possession of drugs for personal use into treatment where appropriate.
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