A breakthrough drug which directly targets middle-aged spread could help millions of overweight Britons to lose weight.

Slimmers taking the pills lost three times as much weight as those simply trying to diet and exercise, a landmark trial found. The drug also cut the risk of diabetes by a fifth.

Experts hailed lorcaserin as the most effective weight-loss pill yet, suggesting it could help the two in three adults battling weight problems.

The approach could be “the Holy Grail” in the battle to combat obesity, they said.

The US research, which tracked 12,000 obese or overweight adults, found that four in ten of those taking the drug lost a significant amount of weight over the course of a year.

On average, slimmers taking the twice-daily pills lost nine pounds - around a dress size for the average woman - while those who stuck to traditional diet tips shed just three pounds.

And more than three years after the trial began, they had kept the weight off, the study found.