Liberal Democrat leader Sir Ed Davey has insisted his support for legalising cannabis is not “inconsistent” with backing a phased smoking ban.

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.

Under the Conservative Party’s plans, each year the legal age for cigarette sales – currently 18 – would increase by one year.

It would mean people born in or after 2009 will never be able to legally buy cigarettes.

The proposals would not affect those who are already allowed to buy cigarettes.

However, critics argue this would create a “black market”, which is unregulated.

Although there was not time to pass the law before the election, the Tories have recommitted to the policy in their manifesto.

Labour has also pledged to bring in the ban if it wins power.

Neither party has plans to legalise any drugs.

The Scottish National Party manifesto pledges to decriminalise drugs for personal use.

Meanwhile, the Green Party manifesto promises a National Commission to agree on an evidence-based approach to reform of drug laws to allow the UK to “move towards a legally regulated market”.

It says any elected Green MPs would “push to decriminalise the personal possession of drugs”.

Reform UK has pledged mandatory life imprisonment for drug dealing and a new offence of Substantial Possession of Drugs carrying heavy fines.