The open display of tobacco products is set to be banned
Subtle branding on cigarette packets is misleading smokers into believing some products are less harmful than others, research suggests.
Products branded "smooth", "silver" or "gold" are generally believed to be healthier and easier to give up, a survey of 1,300 people found.
But when shown plain packs the false beliefs disappeared, University of Nottingham researchers discovered.
EU rules ban any claims that some cigarettes are safer than others.
Participants in the study were shown pairs of cigarette packs and asked to compare what they were like, or what they assumed they would be like, in terms of taste, tar levels, health risk, attractiveness, how easy they would be to give up and how attractive they would be to someone choosing to smoke for the first time.
The results from 800 adult smokers and 500 teenagers, all in the UK, also showed that lighter-coloured packaging led people to believe the cigarettes had a lower tar content or were generally less harmful.
More than half of adults and teenagers reported that among the eight brands they were shown those labelled "smooth" were less harmful than the regular variety.
Marlboro packs with a gold label were rated as having a lower health risk by 53% of adults and easier to quit by 31%, when compared with the Marlboro packs with a red logo.
When shown packs where the branding had been removed, false beliefs about the risk of harm or addiction dropped significantly.
Since 2002 it has been illegal under EU legislation for manufacturers to use trademarks, text or any sign to suggest that one tobacco product is less harmful than another.
Banned phrases include "low tar", "light" and "mild".
In the UK, the Liberal Democrats are currently trying to reintroduce an amendment to the Health Bill to further restrict branding and designs on packs.
Writing in the European Journal of Public Health, the researchers said the regulations were failing to remove "potentially misleading" information from cigarettes.
Professor David Hammond, from the Department of Health Studies and Gerontology at the University of Waterloo in Ontario, Canada, said: "The truth is that all cigarettes are equally hazardous, regardless of what colour the pack is or what words appear on it.
"These tactics are giving consumers a false sense of reassurance that simply does not exist."
Christopher Ogden, chief executive of the Tobacco Manufacturers' Association, said it did not believe proposals for plain packaging were based on sound public policy or compelling evidence.
"Plain packaging would prevent tobacco manufacturers from providing consumers with information about products that are legally available in retail outlets.
"Adult smokers use packaging to identify, obtain information about and choose tobacco products, easily and without confusion."
He added the evidence in support of mandatory plain packaging was "speculative".
Deborah Arnott, chief executive of Action on Smoking and Health, said the research showed all tobacco products should be sold in plain packaging.
"That would remove false beliefs about different brands and communicate the message that all cigarettes are dangerous.
"This matter has been discussed by Parliament and there is now a perfect opportunity to include a requirement for plain packaging of tobacco products in the Health Bill."