Tobacco giant Philip Morris has been accused of "staggering hypocrisy" over its campaign urging smokers to quit.
The firm said the campaign, called Hold My Light, is an "important next step" in the company’s path to "ultimately stop selling cigarettes".
But Cancer Research said the company is only trying to promote its smoking alternatives such as e-cigarettes and heated tobacco.
George Butterworth, from Cancer Research UK, said: "This is a staggering hypocrisy from a tobacco company to promote its own smoking cessation products in the UK while continuing to promote tobacco cigarettes across the world.
"The best way Philip Morris could help people to stop smoking is to stop making cigarettes.
"Smoking is the leading preventable cause of cancer and we encourage people to switch away completely from smoking, including through the use of e-cigarettes.
"We would also advise smokers to fully give up and not continue to smoke tobacco whilst using an e-cigarette."
Peter Nixon, managing director of Philip Morris Limited, said: "There are more options than ever before for smokers to give up cigarettes but often they don’t realise that alternatives, like e-cigarettes and heated tobacco are a better choice than continuing to smoke.
"Our research has shown that smokers want personal support from friends and family if they are to give up cigarettes - and that is what Hold My Light is designed to offer."
The idea of the campaign is a 30-day challenge based on a pledge between a smoker and their supporters.