The National Institute for Health and Clinical Excellence (Nice) issued guidance on the use of varenicline (Champix).

The twice-daily pill works by providing relief from cravings and the withdrawal symptoms experienced by smokers. It also reduces the satisfaction a smoker will get from further cigarettes if they have a relapse.

Trials have shown the drug was effective after a 12-week course, with 44% of smokers managing to stop. This compared to 18% of those given a placebo and 30% of those taking another anti-smoking drug, Zyban, also available on the NHS.

People can take Champix for longer than 12 weeks if recommended by their doctor.

The cost of a 56-day pack of tablets is £54.60. The recommended 12-week course of treatment costs about £163.80. The Nice guidance is subject to appeal, with final approval tabled for July.

A spokeswoman for Nice said: "Having looked at all the evidence, our independent committee have concluded that varenicline appears to be a good way to help people who want to quit smoking.

"The draft guidance also recommends that varenicline should normally be provided in conjunction with counselling and support, but if such support is not available, this should not stop smokers receiving treatment with varenicline.

"Stakeholders now have the opportunity to appeal against the draft guidance. Subject to any appeal, final guidance is expected to be issued to the NHS in July 2007."

The draft approval comes just weeks before England goes smoke-free on July 1, when there will be a ban on smoking in virtually all enclosed work and public places.