Tax increases on cigarettes have long been a drag for the nicotine-addicted and now research suggests that price hikes cause smokers to inhale more deeply. The findings suggest that higher prices for tobacco - justified by the Treasury on public health grounds - could cause more harm than good.
"When the cost of cigarettes is increased, people smoke fewer cigarettes, but they smoke each one more deeply," said Francesca Cornaglia, an economics lecturer at University College London.
"In the economics literature, people just look at the number of cigarettes (consumed). But the same cigarettes can be smoked in different ways. If you smoke to the very end, the filter won't work properly and more bad substances are introduced," she said.
Dr Cornaglia and co-author Jerome Adda examined smoking trends in the US and UK between 1993 and 2001, scouring data on levels of cotinine, a by-product of nicotine breakdown in smokers' blood and used to measure smoking intensity.
"Taxing cigarettes provides a larger income of money at state level, but then we have to spend more because smokers are compensating by smoking more intensely. It actually has perverse effects," Dr Cornaglia said.
The study also says that the increase in the intensity of smoking could explain the steady increase in deep lung cancers in the US since the early 1950s.
In March this year, Chancellor Gordon Brown announced a 7p increase on a packet of 20 cigarettes "for public health reasons". The average packet now costs £4.92.
Dr Cornaglia and Dr Adda's findings were presented at this week's Econometric Society World Congress 2005 at UCL.