The company said its end-of-year pre-tax profits would be around £10.5 million, £3 million lower than most City analysts' forecasts.

The news follows a series of disappointing trading statements from the company.

At its interim results, the company said like-for-like sales, which exclude the effect of store openings and closures, were down 3.8 per cent over the Christmas period.

Today the company, which has several outlets in Sussex, said that the slide had worsened and like-for-like sales in the 44 weeks to May 1 were down five per cent.

But at the same time the company said sales through its own stores were up 11 per cent due to a store-opening programme.

The company said the profit warning was mainly the results of a deliberate cut-back in new product launches, advertising and promotion during a period of investment.

The group has spent £53 million on a new manufacturing facility, a distribution centre and on new point-of-sale equipment for its stores.

With the investment complete, the company said it would begin a range of new product launches to "regain sales momentum by the autumn".

Roger Paffard, chief executive at Thorntons, said: "While these sales figures are disappointing, we are confident that our strategic plan remains robust.

"The group underestimated the amount of new product necessary to stimulate sales over Mothers' Day and Easter.

"With the major infrastructure investment successfully completed, we can now focus on regenerating sales momentum in time for the key Christmas season."

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