'570 children a day' start smoking
About 207,000 11 to 15-year-olds take up smoking every year in the UK, a charity has warned.
Cancer Research UK said government figures suggested 570 children smoked for the first time every day.
The charity urged the government to commit to plain, standardised packaging of tobacco, which is considered less appealing to youngsters.
The figures come from an annual Smoking, Drinking and Drug Use Among Young People in England survey.
Results for smoking rates at each age group in 2011 were compared with smoking rates in the same group the year before and extrapolated to the UK population.
About 27% of all under-16s have tried smoking at least once - equivalent to one million children, the figures suggest.
And eight out of 10 adult smokers started before they turned 19.
The total number of children who started smoking was 50,000 higher than the 2010 figure of 157,000.
Data also suggested that children smoked more and more as they got older, Cancer Research UK said.
The survey among 12-year-olds in 2010 found none was a regular smoker, 1% smoked occasionally and 2% said they used to smoke.
But a year later in 2011, among the same group of children, now aged 13, 2% were found to smoke regularly, 4% smoked occasionally and 3% said they used to smoke.
Half of all long-term smokers will die from tobacco-related illness, which causes 100,000 deaths a year.
The charity called on the government to commit to the plain packaging plan, as was introduced in Australia in December 2012.
A public consultation on the future of tobacco packaging closed in August 2012, but there has been no decision on whether it will be introduced. It follows a ban on tobacco displays in shops.
Research has shown that children find plain packs less appealing and are less likely to be misled by the sophisticated marketing techniques designed to make smoking attractive to youngsters, Cancer Research UK said.
Sarah Woolnough, the charity's executive director of policy and information, said: "With such a large number of youngsters starting to smoke every year, urgent action is needed to tackle the devastation caused by tobacco.
"Replacing slick, brightly coloured packs that appeal to children with standard packs displaying prominent health warnings is a vital part of efforts to protect health.
"Reducing the appeal of cigarettes with plain, standardised packs will give millions of children one less reason to start smoking."
Public Health Minister Anna Soubry said: "It's worrying that these figures show that more 15-year-olds are trying cigarettes.
"We have consulted on introducing standardised packaging, looking at whether this could reduce smoking in young people. We have an open mind about this.
"Any decisions to take further action will be taken only after full consideration of the consultation responses and evidence."
The Tobacco Manufacturers Association said: "The percentage of children who smoke in this country is at an all-time low - 5%.
"There is no credible evidence that the proposals for plain packaging will have an impact on youth smoking rates - in fact it could actually increase youth smoking by driving the availability of smuggled tobacco being sold by criminals in local communities."
Simon Clark, from the campaign group Forest, said: "There is no credible evidence that plain packaging will reduce youth smoking rates. The main reasons teenagers start smoking is because of peer pressure and parental influence, not packaging."