The company, the third-largest drugmaker in the world, made �1.69bn ($2.84bn) in the three months to September, up 24% on the same period the year before.

The sharp rise, ahead of expectations, comfortably exceeded an increase in sales of 9% to �5.47bn.

But its prediction for the whole of 2003 remained unchanged at "single-digit or better" percentage growth - a forecast some analysts described as disappointing.

In afternoon trading, GSK shares were down 20 pence at �12.74, a fall of 1.5% on the day.

The news came as third-quarter figures from US competitors Pfizer and Merck fell short of analysts' hopes.

Pfizer said its profits were $2.29bn - down from $2.35bn a year earlier - once special charges of $1.28bn for the purchase of Pharmacia were taken into account, although the acquisition brought a raft of new drugs which boosted sales by 56% to $12.5bn.

And Merck turned in earnings of $1.83bn, slightly down on last year on only modestly-rising sales, as it warned that it was embarking on a restructuring that would cost about 4,400 jobs.

Generic threat

GSK is facing problems in the US as competition builds to its blockbuster antidepressant Paxil.

Competitors are now selling generic equivalents to Paxil, at a time when GSK's pipeline of new drugs - including new medicaments for cancer and heart disease - is unlikely to produce market-ready products till 2005.

Like many of its peers, the company has also been hit by criticism that it is not doing enough to help fight the HIV/Aids pandemic infecting huge swathes of Africa and Asia.

Earlier this month the South Africa's competition watchdog said it had failed to make life-saving Aids treatments available to the poor, threatening it with fines of up to 10% of its annual Aids drugs sales in South Africa.