Researchers today hailed the latest results from trials of a pill which treats obesity, tackles cholesterol levels and helps patients quit smoking.

Rimonabant, which could be available in the UK within 18 months, targets the part of the brain involved in motivation and controlling appetite.

The latest results of a two-year trial, presented at the American Heart Association Scientific Sessions in New Orleans, showed that patients taking a 20mg dose had seen their body weight drop and waist measurements decrease.

Xavier Pi-Sunyer, one of the researchers, said they also found a significant increase in HDL cholesterol (good cholesterol) in the patients.

Rimonabant, which some have described as a "wonder pill", is being developed for the management of cardiovascular risk factors, including reducing abdominal obesity, and as an aid to smoking cessation.

David Haslam, the chairman of the National Obesity Forum, described the arrival of the drug in Britain as "a mouth-watering prospect" for GPs.

"This is a completely unique drug and these are very impressive results," he said. "We can really save some lives with this as well as reducing the large costs of treating obesity and its related complications such as heart disease in the NHS. The cost of treating obesity is phenomenal."

The latest findings from trials involving more than 3,000 patients in the US and Canada revealed that those taking rimonabant lost more weight around their waist than those taking dummy pills.

It is estimated that more than one in five Britons is now classed as obese and three-quarters are overweight.

The drug, made by Sanofi-Synthelabo, will be sold under the trade name Acomplia.