Smokers will be banned from buying cigarettes until they are 21 as part of measures to improve public health being considered by the government.

An influential cross-party group of MPs has proposed raising the minimum smoking age and introducing a levy on big tobacco companies to fund measures to encourage people to quit and to prevent youngsters taking up the habit.

The parliamentary group on smoking and health, backed by 17 health charities and medical organisations, also wants to tighten the rules on showing smoking on TV and in films.

“Smoking remains the leading cause of premature death and health inequalities,” said Tory MP Bob Blackman, chair of the group. “Ratcheting up tobacco regulation further and faster is essential to achieve the government’s vision for prevention, to increase healthy life expectancy while reducing inequalities between the richest and poorest in society.”

The group, which was instrumental in introducing plain packaging and banning smoking in public places, believes it is pushing at an open door.

The health secretary, Matt Hancock, says tackling smoking rates is key to the government’s plans to increase healthy life expectancy by five years by 2035. In England, the Department of Health wants to reduce the prevalence of 15-year-olds who regularly smoke from 8% to 3% or less and reduce smoking among adults from 15.5% to 12% or less by the end of 2022.

Hancock has said the government is prepared to introduce new legislation to curb smoking rates. “Smoking remains one of the biggest causes of years of life lost in Britain and other countries,” said David Halpern, who heads the government’s behavioural insight team or “nudge” unit. “The good news is that we have learned a great deal about how to help smokers quit. Pushing forward on this agenda is one of our single best bets to extend life expectancy in the UK, particularly among disadvantaged communities.”

The group’s submission to the government’s green paper is backed by Action on Smoking and Health, and 16 other health and welfare organisations, including the British Medical Association, Cancer Research UK, the Royal College of Physicians and the British Heart Foundation. It also calls for the collection and publication of tobacco manufacturers’ sales and marketing data, to monitor the evolving behaviour of the industry, and inserts for cigarette packs with messages encouraging people to quit. There would also be increased funding for education campaigns on social and mass media.

Baroness Finlay, a vice-chair of the group, said action was needed because “smoking rates among young people have now started to flatline and the inequalities gap is widening”.

Raising the age limit at which people can buy cigarettes to 21 would put the UK on a par with only a few countries and cities in the world, including Honduras, Kuwait and New York City. But it is the introduction of a levy, now said to be under serious consideration by ministers, that could prove the most alarming to the tobacco industry.

Under the new proposal, each tobacco manufacturer would effectively have to pay an annual fee based on the volume of smoked cigarettes it sold in the UK, potentially raising hundreds of millions of pounds. But the tobacco industry has fought hard to resist successive governments from introducing legislation that would reduce its profits.Deborah Arnott, chief executive of Ash, said: “Legislation to strictly regulate smoking used to be considered controversial and extreme by all mainstream political parties but governments now have confidence that tough tobacco regulation both delivers results, and, crucially, has widespread cross-party and public support.”