Smoking a single cigarette could take 20 minutes off your life - Study
Each cigarette a person smokes could shorten their life by 20 minutes, according to new estimates.
The new figures are an increase on previous estimates, which suggested a cigarette shortens a smoker's life by 11 minutes.
The data suggests if a 10-a-day smoker quits on January 1, then by January 8 they could "prevent loss of a full day of life".
By February 20, their lives could be extended by a whole week.
If their quitting is successful until August 5, they will likely live for a whole month longer than if they had continued to smoke.
The figures come from analysis commissioned by the Department for Health and Social Care and carried out by researchers from University College London (UCL).
According to the new estimates, the average man loses 17 minutes of life with every cigarette they smoke, while a woman's life is cut short by 22 minutes with each cigarette.
Researchers analysed up-to-date figures from long-term studies tracking the health of the population.
They said that the harm caused by smoking is "cumulative" and the sooner a person stops smoking, and the more cigarettes they avoid smoking, the longer they live.
The authors added: "Studies suggest that smokers typically lose about the same number of healthy years as they do total years of life.
"Thus smoking primarily eats into the relatively healthy middle years rather than shortening the period at the end of life, which is often marked by chronic illness or disability.
"So a 60-year-old smoker will typically have the health profile of a 70-year-old non-smoker."
The analysis, to be published in the Journal of Addiction, concludes: "We estimate that on average, smokers in Britain who do not quit lose approximately 20 minutes of life expectancy for each cigarette they smoke.
"This is time that would likely be spent in relatively good health.
"Stopping smoking at every age is beneficial but the sooner smokers get off this escalator of death the longer and healthier they can expect their lives to be."
Dr Sarah Jackson, principal research fellow from the UCL Alcohol and Tobacco Research Group, said it was "vital that people understand how much quitting can improve their life expectancy".
"The sooner a person stops smoking, the longer they live. Quitting at any age substantially improves health and the benefits start almost immediately."
Public health minister Andrew Gwynne said: "Smoking is an expensive and deadly habit and these findings reveal the shocking reality of this addiction, highlighting how important it is to quit.
"The new year offers a perfect chance for smokers to make a new resolution and take that step."