THE cost of tobacco is still affordable to many millions of smokers in the UK despite rising prices, a study suggests.

Researchers are calling for larger tax rises to make the country's nine million smokers realise their habit is unaffordable.

They have developed a new way of calculating affordability for tobacco in the UK, which shows that despite price rises, smoking has only become a little less affordable but not enough to change behaviour.

Raising cigarette prices through tobacco taxation reduces smoking, but it is affected by smokers' income and the prices of different types of brands and products.

Researchers at King's College London and the University of Bath found that year-on-year the costs of tobacco products were rising - 2.6% for factory-made cigarettes and 4.5% for roll-your-own tobacco.

But despite falling incomes this only contributed to a small decrease in affordability among those most hooked on smoking.

In 2002, smokers of factory-made cigarettes kept 92% of their income after paying for their vice and by 2014 this had gone down to 88%.

For the first time, the researchers were able to assess the affordability of roll-your-own tobacco and found that this was more affordable.

Roll-your-own tobacco smokers kept 96.3% of their income after paying for their roll-ups in 2006 which went down to 93.7% in 2014.

Lead author Dr Timea Partos, from King's College London, said: "We know that in general, increasing tax on tobacco reduces smoking and that the tobacco industry keeps some products cheap to counter the effect of tax rises.

"Using our new method which assesses affordability to individual smokers, we have shown that price rises don't necessarily translate to less affordable tobacco."

Dr Rob Branston, of the University of Bath, said that if prices are going to have an effect on changing behaviours, consumers need to feel it at the till.

He said: "Smokers can currently offset tax rises by adjusting their smoking behaviour so they don't get a strong enough push to quit the deadly habit.

"Larger tax rises are needed to make smokers realise it is an unaffordable habit."

The heaviest smokers are spending between 2% for roll-your-own tobacco and 4% more for factory-made cigarettes of their incomes than those least dependent. In 2014 this equated to around £500 to £1,000 each year.

The researchers' new individualised measure for affordability takes individual income and variation in consumption into account, including the use of roll-your-own tobacco and illicit products.

Professor Ann McNeill, from King's College London, added: "Smoking is largely invisible in high-income communities but still common among the poor and disadvantaged in society.

"Price is a key motivator to stop smoking, so we must optimise taxation policy to reach all smokers, as well as provide the support that smokers need to stop."

- The study, Individualised tobacco affordability in the UK 2002-2014: Findings from the International Tobacco Control Policy Evaluation Project, is published in BMJ journal Tobacco Control.