Despite being too young to legally purchase tobacco products, the number of those aged between 11 and 15 choosing to smoke has risen by 50,000 in just one year.
The figure equates to 567 children taking up the smoking each day, the charity said.
Sarah Woolnough, executive director of policy and information at Cancer Research UK, warned that most long term smokers take up the habit in childhood.
Almost one in three (27%) of under-16s have tried smoking at least once, the study by the charity found.
It urged the Government to commit to putting all cigarettes in plain standardised packs.
Last April, the Government launched a consultation on plans to introduce mandatory standardised packaging for tobacco products.
Health campaigners have welcomed the proposal, but opponents claimed it would lead to increased smuggling and job losses.
Information generated by the consultation, which closed in August, is still being analysed by health officials.
Sarah Woolnough, executive director of policy and information at Cancer Research UK, 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.
“These figures underline the importance of sustained action to discourage young people from starting.
“Smoking kills and is responsible for at least 14 different types of cancer. Standardised packaging is popular with the public and will help protect children.
“We urge the Government to show their commitment to health and introduce plain, standardised packs as soon as possible.”
Culled from telegraph.co.uk