The Anglo-Dutch firm said tough economic conditions had taken their toll on sales of its core brands, which include Dove soap and Magnum ice cream, in the first half of the year.

It said it now expects sales to grow by just 4% this year, as opposed to earlier forecasts of between 5% and 6%.

But the company rushed to defend its Path to Growth stragegy, which has seen it slash its brand portfolio back to 400 core products.

A spokesman said it remained "as valid today as it did at the beginning of the programme" in 2000.

The slump in air travel has hit its top end products such as its Calvin Klein range, it said.

While sales of its Slimfast product have been affected by growing trend in the US towards low carbohydrate diets.

The statement was enough to send Unilever's share price tumbling, to close 62p lower at 497p.

The FTSE 100 index of leading shares closed down 72 points at 4,088.