Champix is the first non-nicotine drug that's been developed for smoking cessation. It has on effect on the body similar to that of nicotine and is thought to both reduce the desire to smoke and lessen withdrawal symptoms.

The drug is available by prescription only and costs ?2 (close to $4) a day.

A year after the trials concluded, 22.5 percent of participants who used Chambix were still non-smokers, while only 15.7 percent of those treated with Zyban and 9.4 of those treated with placebo were able to remain smoke-free.

Dr. Alex Bobak, a London GP who has carried out trials on the drug, said, according to BBC News, "It's more effective than current alternatives and is a significant advance.

"Having more than 20 percent of smokers still stopped after a year is very good, although it's important to stress the need for support from healthcare professionals while you're doing it."

It's expected there will be a big demand for the drug, as a ban on smoking in public places in England is taking effect next July.

Deborah Arnott, director of the charity Action and Smoking on Health, said: "Varenicline appears to be a useful additional aid to stopping smoking. We anticipate that there will be significant demand for this new drug, given that more than 70 percent of smokers say that they would like to stop smoking.

"We trust that the new guidance will help practitioners prescribe the drug to those patients who are most likely to benefit from it."

The drug could make millions worldwide if it proves successful. It has already been licensed in the United States and some other countries.