A cigarette stub is seen in an ashtray on a street in Liverpool , northern England October 17 , 2016. REUTERS/Phil Noble

LONDON (Reuters) - The introduction of plain packaging for tobacco cigarettes sold in Britain from next month could cut the number of smokers in the country by another 300,000 within a year, researchers said on Thursday.

Based on observational evidence and a review of more than 50 experimental studies on the potential impact of plain packs, experts from the Cochrane Review said they appear to diminish the appeal of tobacco and help reduce smoking prevalence.

Australia was the first country in the world to implement standardized packaging of tobacco products, in December 2012, and data collected since then suggest the new measure led to an extra 0.5 percent a year decline in the number of smokers there.

British legislation on plain packaging for tobacco comes into full effect from May 2017. Plain or standardised packs must be a uniform colour, have no logos apart from health warnings and other government-mandated information, and use a prescribed uniform font, colour and size for the brand name.

“We are not able to say for sure what the impact would be in the UK, but if the same magnitude of decrease was seen.. as was observed in Australia, this would translate to roughly 300,000 fewer (UK) smokers,” said Jamie Hartmann-Boyce, a researcher at the Cochrane Tobacco Addiction Group in Oxford.

According to the World Health Organization, tobacco kills more people worldwide than any other preventable cause of death.

The introduction of plain packaging is recommended under the WHO’s Framework Convention on Tobacco Control (FCTC).

The Cochrane team analysed 51 studies and sought to analyse and summarise their findings. This was hampered by the fact that many of the studies differed in the way they were done and also what they measured, and the fact that so far, only one country had implemented standardised packaging.

“Our evidence suggests standardised packaging can change attitudes and beliefs about smoking, and the evidence we have so far suggests that standardised packaging may reduce smoking prevalence and increase quit attempts,” Hartmann-Boyce said.